-TDELTA_TIME
-TDICT
-TDICT_CACHE
+-TDICT_CACHE_SREQ
+-TDICT_CACHE_SREQ_INFO
+-TDICT_CACHE_TEST
-TDICT_CDBM
-TDICT_CDBQ
-TDICT_CIDR
20131219
Cleanup: renamed postconf(1) internal identifiers according
- to a consistent scheme, to avoid name future name conflicts
- as Postfix evolves. This is a no-feature change. Files:
+ to a consistent scheme, to avoid future name conflicts as
+ Postfix evolves. This is a no-feature change. Files:
postconf/*.[hc], postconf/extract.awk.
Documentation: linearized the order of exposition in
Documentation: added section on how to verify that forward
secrecy works. File: proto/FORWARD_SECRECY_README.html.
+
+20131222
+
+ Documentation: forward secrecy, with feedback from Adam
+ Shostack. Viktor Dukhovni and Wietse Venema. File:
+ proto/FORWARD_SECRECY_README.html.
+
+20131224
+
+ Feature: smtpd_sasl_service (until now, this was hard-coded
+ internally as "smtp"). On request by Michal (sksoft.cz).
+ Files: global/mail_params.h, proto/postconf.proto,
+ mantools/postlink, smtpd/smtpd.c, smtpd/smtpd_sasl_glue.c.
+
+ Documentation: updated example to Dovecot version 2 syntax.
+ File: proto/SASL_README/html.
+
+20131228
+
+ Cleanup: DANE support: test script. Viktor Dukhovni. File
+ tls/tls_dane.sh.
+
+ LMDB will not be supported in the stable Postfix 2.11 release.
+
+ Debugging: test driver to speed up LMDB debugging and stress
+ testing. Shockingly, LMDB terminates the postcreen daemon
+ without logfile record. Fixing this will require changes
+ in LMDB or changes in the way Postfix can use LMDB. File:
+ util/dict_cache.c.
-------------------------------------------------------------------------------
+W\bWa\bar\brn\bni\bin\bng\bg
+
+Forward secrecy does not protect against active attacks such as forged DNS
+replies or forged TLS server certificates. If such attacks are a concern, then
+the SMTP client will need to authenticate the remote SMTP server in a
+sufficiently-secure manner. For example, by the fingerprint of the public key
+or certificate. Conventional PKI relies on many trusted parties and is easily
+subverted by a state-funded adversary.
+
B\bBa\bac\bck\bkg\bgr\bro\bou\bun\bnd\bd
Postfix supports forward secrecy of TLS network communication since version
traffic is generally infeasible, and even recovery of individual sessions may
be infeasible given a sufficiently-strong key agreement method.
-Forward secrecy protects network communication in the absence of active
-attacks, i.e. no forged DNS replies, and no forged TLS server certificates. If
-active attacks are a concern, then you will need to authenticate the remote
-SMTP server in a secure manner. For example, by the fingerprint of the public
-key or certificate. Conventional PKI relies on too many trusted parties.
-
Topics covered in this document:
* Forward Secrecy in TLS
* Forward Secrecy in the Postfix SMTP Server
* Forward Secrecy in the Postfix SMTP Client
- * How do I know that it works?
+ * Getting started, quick and dirty
+ * How can I see that a connection has forward secrecy?
+ * What ciphers provide forward secrecy?
+ * What do "Anonymous", "Untrusted", etc. in Postfix logging mean?
* Credits
And last but not least, for the impatient:
The key-exchange algorithms used for forward secrecy require the TLS server to
designate appropriate "parameters" consisting of a mathematical "group" and an
-element of that group called a "generator". There are two flavors of "groups"
-that work with PFS:
+element of that group called a "generator". Presently, there are two flavors of
+"groups" that work with PFS:
- * Prime field groups. The server needs to be configured with a suitably large
- prime and a corresponding "generator".
- * Elliptic curve groups. The server needs to be configured with a "named
- curve". These offer better security at lower computational cost than prime
- field groups, but are not as widely implemented.
+ * P\bPr\bri\bim\bme\be-\b-f\bfi\bie\bel\bld\bd g\bgr\bro\bou\bup\bps\bs (\b(E\bED\bDH\bH)\b):\b: The server needs to be configured with a
+ suitably-large prime and a corresponding "generator". The acronym for
+ forward secrecy over prime fields is EDH or Ephemeral Diffie-Hellman
+ (sometimes also abbreviated as DHE).
-The acronym for forward secrecy over prime fields is EDH or Ephemeral Diffie-
-Hellman (sometimes also abbreviated as DHE). The acronym for the elliptic curve
-version is EECDH which is short for Ephemeral Elliptic Curve Diffie-Hellman.
+ * E\bEl\bll\bli\bip\bpt\bti\bic\bc-\b-c\bcu\bur\brv\bve\be g\bgr\bro\bou\bup\bps\bs (\b(E\bEE\bEC\bCD\bDH\bH)\b):\b: The server needs to be configured with a
+ "named curve". These offer better security at lower computational cost than
+ prime field groups, but are not as widely implemented. The acronym for the
+ elliptic curve version is EECDH which is short for Ephemeral Elliptic Curve
+ Diffie-Hellman.
It is not essential to know what these are, but one does need to know that
OpenSSL only supports EECDH as of version 1.0.0. Thus the configuration
late 2013 (it is available only in OpenSSL development snapshots).
At some point Postfix will need to adjust to the new API for setting the
-elliptic curve options. Fortunately, when EECDH support was added to Postfix,
+elliptic-curve options. Fortunately, when EECDH support was added to Postfix,
it introduced a layer of indirection:
smtpd_tls_eecdh_grade = strong | ultra
F\bFo\bor\brw\bwa\bar\brd\bd S\bSe\bec\bcr\bre\bec\bcy\by i\bin\bn t\bth\bhe\be P\bPo\bos\bst\btf\bfi\bix\bx S\bSM\bMT\bTP\bP C\bCl\bli\bie\ben\bnt\bt
The Postfix >= 2.2 SMTP client supports forward secrecy in its default
-configuration. If the remote SMTP server supports cipher suites with forward
-secrecy (and does not override the SMTP client cipher preference), then the
-traffic between the server and client will resist decryption even if the
-server's long-term authentication keys are later compromised.
+configuration. No configuration changes are needed besides turning on elliptic-
+curve support with Postfix 2.6 and 2.7 (see the quick-start section). If the
+remote SMTP server supports cipher suites with forward secrecy (and does not
+override the SMTP client's cipher preference), then the traffic between the
+server and client will resist decryption even if the server's long-term
+authentication keys are later compromised.
The default Postfix SMTP client cipher lists are correctly ordered to prefer
EECDH and EDH cipher suites ahead of similar cipher suites that don't implement
G\bGe\bet\btt\bti\bin\bng\bg s\bst\bta\bar\brt\bte\bed\bd,\b, q\bqu\bui\bic\bck\bk a\ban\bnd\bd d\bdi\bir\brt\bty\by
-At least one time as root (prime group generation can take a few seconds to a
-few minutes):
+ * Postfix 2.6 and 2.7: Enable elliptic-curve support. This is the default
+ with Postfix >= 2.8.
+
+ /etc/postfix/main.cf:
+ # Postfix 2.6 or 2.7 only. This is default with Postfix 2.8 and
+ later.
+ smtpd_tls_eecdh_grade = strong
+
+ * Optionally generate non-default EDH parameters for improved security
+ against pre-computation attacks and for compatibility with Debian-patched
+ EXIM SMTP clients (these require a minimum 2048-bit length for the non-
+ export prime). The parameter files are not secret, after all these
+ parameters are sent to all SMTP clients in the clear. Mode 0644 is fine.
+
+ Execute as root (prime group generation can take a few seconds to a few
+ minutes):
- # cd /etc/postfix
- # openssl dhparam -out dh512.tmp 512 && mv dh512.tmp dh512.pem
- # openssl dhparam -out dh1024.tmp 1024 && mv dh1024.tmp dh1024.pem
- # openssl dhparam -out dh2048.tmp 2048 && mv dh2048.tmp dh2048.pem
- # chmod 644 dh512.pem dh1024.pem dh2048.pem
+ # cd /etc/postfix
+ # openssl dhparam -out dh512.tmp 512 && mv dh512.tmp dh512.pem
+ # openssl dhparam -out dh1024.tmp 1024 && mv dh1024.tmp dh1024.pem
+ # openssl dhparam -out dh2048.tmp 2048 && mv dh2048.tmp dh2048.pem
+ # chmod 644 dh512.pem dh1024.pem dh2048.pem
-Note: greater security against "pre-computation" attacks against EDH can be
-obtained by periodically regenerating the EDH parameters as above (an hourly or
-daily cron job running as root can automate this task). The parameter files are
-not secret, after all these are sent to all SMTP clients in the clear. Mode
-0644 is fine.
+ You can improve security against pre-computation attacks further by
+ regenerating the EDH parameters periodically (an hourly or daily cron job
+ running as root can automate this task).
-Once the parameters are in place, update main.cf as follows:
+ Once the parameters are in place, update main.cf as follows:
- /etc/postfix/main.cf:
- # Postfix >= 2.6
- smtpd_tls_eecdh_grade = strong
- # All versions of Postfix:
- smtpd_tls_dh1024_param_file = ${config_directory}/dh2048.pem
- smtpd_tls_dh512_param_file = ${config_directory}/dh512.pem
+ /etc/postfix/main.cf:
+ smtpd_tls_dh1024_param_file = ${config_directory}/dh2048.pem
+ smtpd_tls_dh512_param_file = ${config_directory}/dh512.pem
-If some of your MSA clients don't support 2048-bit EDH, you may need to adjust
-the submission entry in master.cf accordingly:
+ If some of your MSA clients don't support 2048-bit EDH, you may need to
+ adjust the submission entry in master.cf accordingly:
- /etc/postfix/master.cf:
- submission inet n - n - - smtpd
- # Some submission clients may not yet do 2048-bit EDH, if such
- # clients use your MSA, configure 1024-bit EDH instead:
- -o smtpd_tls_dh1024_param_file=${config_directory}/dh1024.pem
- -o smtpd_tls_security_level=encrypt
- -o smtpd_sasl_auth_enable=yes
- ...
+ /etc/postfix/master.cf:
+ submission inet n - n - - smtpd
+ # Some submission clients may not yet do 2048-bit EDH, if such
+ # clients use your MSA, configure 1024-bit EDH instead:
+ -o smtpd_tls_dh1024_param_file=${config_directory}/dh1024.pem
+ -o smtpd_tls_security_level=encrypt
+ -o smtpd_sasl_auth_enable=yes
+ ...
-H\bHo\bow\bw d\bdo\bo I\bI k\bkn\bno\bow\bw t\bth\bha\bat\bt i\bit\bt w\bwo\bor\brk\bks\bs?\b?
+H\bHo\bow\bw c\bca\ban\bn I\bI s\bse\bee\be t\bth\bha\bat\bt a\ba c\bco\bon\bnn\bne\bec\bct\bti\bio\bon\bn h\bha\bas\bs f\bfo\bor\brw\bwa\bar\brd\bd s\bse\bec\bcr\bre\bec\bcy\by?\b?
-Postfix reports TLS connection information in several ways:
+Postfix can be configured to report information about the negotiated cipher,
+the corresponding key lengths, and the remote peer certificate or public-key
+verification status.
* With "smtp_tls_loglevel = 1" and "smtpd_tls_loglevel = 1", the Postfix SMTP
- client and server will log information about, among others, the remote peer
- certificate or public-key verification status, the negotiated cipher, and
- key lengths. The general logfile format is:
+ client and server will log TLS connection information to the maillog file.
+ The general logfile format is:
- postfix/smtp[xxx]: Trusted TLS connection established to
- host.example.com[192.168.0.2]:25: TLSv1 with cipher XXX (YYY/ZZZ bits)
+ postfix/smtp[process-id]: Untrusted TLS connection established
+ to host.example.com[192.168.0.2]:25: TLSv1 with cipher cipher-name
+ (actual-key-size/raw-key-size bits)
- postfix/smtpd[xxx]: Untrusted TLS connection established from
- host.example.com[192.168.0.2]: TLSv1 with cipher XXX (YYY/ZZZ bits)
+ postfix/smtpd[process-id]: Anonymous TLS connection established
+ from host.example.com[192.168.0.2]: TLSv1 with cipher cipher-name
+ (actual-key-size/raw-key-size bits)
* With "smtpd_tls_received_header = yes", the Postfix SMTP server will record
- similar information in the Received: header in the form of comments (text
- inside parentheses). The general format is:
+ TLS connection information in the Received: header in the form of comments
+ (text inside parentheses). The general format depends on the
+ smtpd_tls_ask_ccert setting:
Received: from host.example.com (host.example.com [192.168.0.2])
- (using TLSv1 with cipher XXX (YYY/ZZZ bits))
- (Client CN "host.example.com", Issuer "Wietse Venema" (not
+ (using TLSv1 with cipher cipher-name
+ (actual-key-size/raw-key-size bits))
+ (Client CN "host.example.com", Issuer "John Doe" (not
verified))
+ Received: from host.example.com (host.example.com [192.168.0.2])
+ (using TLSv1 with cipher cipher-name
+ (actual-key-size/raw-key-size bits))
+ (No client certificate requested)
+
+The next sections will explain what cipher-name, key-size, and peer
+verification status information to expect.
+
+W\bWh\bha\bat\bt c\bci\bip\bph\bhe\ber\brs\bs p\bpr\bro\bov\bvi\bid\bde\be f\bfo\bor\brw\bwa\bar\brd\bd s\bse\bec\bcr\bre\bec\bcy\by?\b?
+
There are dozens of ciphers that support forward secrecy. What follows is the
-beginning of a list of 51 ciphers available with OpenSSL 1.0.1e:
+beginning of a list of 51 ciphers available with OpenSSL 1.0.1e. The list is
+sorted in the default Postfix preference order. It excludes null ciphers that
+only authenticate and don't encrypt, together with export and low-grade ciphers
+whose encryption is too weak to offer meaningful secrecy. The first column
+shows the cipher name, and the second shows the key exchange method.
$ openssl ciphers -v \
'aNULL:-aNULL:kEECDH:kEDH:+RC4:!eNULL:!EXPORT:!LOW:@STRENGTH' |
DHE-RSA-AES256-SHA256 Kx=DH
...
+To date, all ciphers that support forward secrecy have one of five values for
+the first component of their OpenSSL name: "AECDH", "ECDHE", "ADH", "EDH" or
+"DHE". Ciphers that don't implement forward secrecy have names that don't start
+with one of these prefixes. This pattern is likely to persist until some new
+key-exchange mechanism is invented that also supports forward secrecy.
+
+The actual key length and raw algorithm key length are generally the same with
+non-export ciphers, but may they differ for the legacy export ciphers where the
+actual key is artificially shortened.
+
+W\bWh\bha\bat\bt d\bdo\bo "\b"A\bAn\bno\bon\bny\bym\bmo\bou\bus\bs"\b",\b, "\b"U\bUn\bnt\btr\bru\bus\bst\bte\bed\bd"\b",\b, e\bet\btc\bc.\b. i\bin\bn P\bPo\bos\bst\btf\bfi\bix\bx l\blo\bog\bgg\bgi\bin\bng\bg m\bme\bea\ban\bn?\b?
+
+The verification levels below are subject to man-in-the-middle attacks to
+different degrees. If such attacks are a concern, then the SMTP client will
+need to authenticate the remote SMTP server in a sufficiently-secure manner.
+For example, by the fingerprint of the public key or certificate. Remember that
+conventional PKI relies on many trusted parties and is easily subverted by a
+state-funded adversary.
+
+A\bAn\bno\bon\bny\bym\bmo\bou\bus\bs (no peer certificate)
+ P\bPo\bos\bst\btf\bfi\bix\bx S\bSM\bMT\bTP\bP c\bcl\bli\bie\ben\bnt\bt:\b: With opportunistic TLS (the "may" security level) the
+ Postfix SMTP client does not verify any information in the peer
+ certificate. In this case it enables and prefers anonymous cipher suites in
+ which the remote SMTP server does not present a certificate (these ciphers
+ offer forward secrecy of necessity). When the remote SMTP server also
+ supports anonymous TLS, and agrees to such a cipher suite, the verification
+ status will be logged as "Anonymous".
+
+ P\bPo\bos\bst\btf\bfi\bix\bx S\bSM\bMT\bTP\bP s\bse\ber\brv\bve\ber\br:\b: This is by far most common, as client certificates are
+ optional, and the Postfix SMTP server does not request client certificates
+ by default (see smtpd_tls_ask_ccert). Even when client certificates are
+ requested, the remote SMTP client might not send a certificate. Unlike the
+ Postfix SMTP client, the Postfix SMTP server "anonymous" verification
+ status does not imply that the cipher suite is anonymous, which corresponds
+ to the server not sending a certificate.
+
+U\bUn\bnt\btr\bru\bus\bst\bte\bed\bd (peer certificate not signed by trusted CA)
+ P\bPo\bos\bst\btf\bfi\bix\bx S\bSM\bMT\bTP\bP c\bcl\bli\bie\ben\bnt\bt:\b: The remote SMTP server presented a certificate, but
+ the Postfix SMTP client was unable to check the issuing CA signature. With
+ opportunistic TLS this is common with remote SMTP servers that don't
+ support anonymous cipher suites.
+
+ P\bPo\bos\bst\btf\bfi\bix\bx S\bSM\bMT\bTP\bP s\bse\ber\brv\bve\ber\br:\b: The remote SMTP client presented a certificate, but
+ the Postfix SMTP server was unable to check the issuing CA signature. This
+ can happen when the server is configured to request client certificates
+ (see smtpd_tls_ask_ccert).
+
+T\bTr\bru\bus\bst\bte\bed\bd (peer certificate signed by trusted CA, unverified peer name)
+ P\bPo\bos\bst\btf\bfi\bix\bx S\bSM\bMT\bTP\bP c\bcl\bli\bie\ben\bnt\bt:\b: The remote SMTP server's certificate was signed by a
+ CA that the Postfix SMTP client trusts, but either the client was not
+ configured to verify the destination server name against the certificate,
+ or the server certificate did not contain any matching names. This is
+ common with opportunistic TLS (smtp_tls_security_level is "may" or else
+ "dane" with no usable TLSA DNS records) when the Postfix SMTP client's
+ trusted CAs can verify the authenticity of the remote SMTP server's
+ certificate, but the client is not configured or unable to verify the
+ server name.
+
+ P\bPo\bos\bst\btf\bfi\bix\bx S\bSM\bMT\bTP\bP s\bse\ber\brv\bve\ber\br:\b: The remote SMTP client certificate was signed by a CA
+ that the Postfix SMTP server trusts. The Postfix SMTP server never verifies
+ the remote SMTP client name against the names in the certificate. Since the
+ client chooses to connect to the server, the Postfix SMTP server has no
+ expectation of a particular client hostname.
+
+V\bVe\ber\bri\bif\bfi\bie\bed\bd (peer certificate signed by trusted CA, verified peer name)
+ P\bPo\bos\bst\btf\bfi\bix\bx S\bSM\bMT\bTP\bP c\bcl\bli\bie\ben\bnt\bt:\b: The remote SMTP server's certificate was signed by a
+ CA that the Postfix SMTP client trusts, and it matches one of the expected
+ server names. This implies that the Postfix SMTP client enforced
+ verification for the destination server name, otherwise the verification
+ status would have been just "Trusted".
+
+ P\bPo\bos\bst\btf\bfi\bix\bx S\bSM\bMT\bTP\bP s\bse\ber\brv\bve\ber\br:\b: The status is never "Verified", as the Postfix SMTP
+ server never verifies the remote SMTP client name against the names in the
+ certificate.
+
C\bCr\bre\bed\bdi\bit\bts\bs
* TLS support for Postfix was originally developed by Lutz Jänicke at Cottbus
+X
+
P\bPo\bos\bst\btf\bfi\bix\bx S\bSA\bAS\bSL\bL H\bHo\bow\bwt\bto\bo
-------------------------------------------------------------------------------
P\bPo\bos\bst\btf\bfi\bix\bx t\bto\bo D\bDo\bov\bve\bec\bco\bot\bt S\bSA\bAS\bSL\bL c\bco\bom\bmm\bmu\bun\bni\bic\bca\bat\bti\bio\bon\bn
Communication between the Postfix SMTP server and Dovecot SASL happens over a
-UNIX-domain socket or over a TCP socket. Dovecot 1 supports UNIX-domain socket
-communication only.
-
-U\bUN\bNI\bIX\bX-\b-d\bdo\bom\bma\bai\bin\bn s\bso\boc\bck\bke\bet\bt c\bco\bom\bmm\bmu\bun\bni\bic\bca\bat\bti\bio\bon\bn
-
-The socket pathname and the list of mechanisms offered to Postfix need to be
-specified on the Dovecot server side in dovecot.conf.
-
-The following example assumes that the Postfix queue is under /var/spool/
-postfix/.
-
-Note: the example uses Dovecot 1 syntax, See http://www.dovecot.org/ for newer
-syntax.
-
- 1 /etc/dovecot.conf:
- 2 auth default {
- 3 mechanisms = plain login
- 4 passdb pam {
- 5 }
- 6 userdb passwd {
- 7 }
- 8 socket listen {
- 9 client {
- 10 path = /var/spool/postfix/private/auth
- 11 mode = 0660
- 12 user = postfix
- 13 group = postfix
- 14 }
- 15 }
- 16 }
-
-Line 3 provides plain and login as mechanisms for the Postfix SMTP server, line
-10 places the Dovecot SASL socket in /var/spool/postfix/private/auth, and lines
-11-13 limit read+write permissions to user and group postfix only.
-
-Proceed with the section "Enabling SASL authentication and authorization in the
-Postfix SMTP server" to turn on and use SASL in the Postfix SMTP server.
-
-T\bTC\bCP\bP s\bso\boc\bck\bke\bet\bt c\bco\bom\bmm\bmu\bun\bni\bic\bca\bat\bti\bio\bon\bn
-
-The TCP port and the list of mechanisms offered to Postfix need to be specified
-on the Dovecot server side in 10-auth.conf and 10-master.conf.
-
-The following examples assume that Postfix should communicate with Dovecot on
-TCP port 12345.
-
-Note: the examples use Dovecot 1 syntax, See http://www.dovecot.org/ for newer
-syntax.
-
- 1 /etc/dovecot/conf.d/10-auth.conf:
- 2 auth_mechanisms = plain login
-
-Line 2 provides plain and login as mechanisms for the Postfix SMTP server.
-
- 1 /etc/dovecot/conf.d/10-master.conf:
- 2 service auth {
- 3 unix_listener auth-userdb {
- 4 }
- 5 inet_listener {
- 6 port = 12345
- 7 }
- 8 }
-
-Line 5 creates a new TCP socket and line 6 specifies port 12345 where Dovecot
-SASL should wait for Postfix authentication requests.
+UNIX-domain socket or over a TCP socket. We will be using a UNIX-domain socket
+for better privacy.
+
+The following fragment for Dovecot version 2 assumes that the Postfix queue is
+under /var/spool/postfix/.
+
+ 1 conf.d/10-master.conf:
+ 2 service auth {
+ 3 ...
+ 4 unix_listener /var/spool/postfix/private/auth {
+ 5 mode = 0660
+ 6 # Assuming the default Postfix user and group
+ 7 user = postfix
+ 8 group = postfix
+ 9 }
+ 10 ...
+ 11 }
+ 12
+ 13 conf.d/10-auth.conf
+ 14 auth_mechanisms = plain login
+
+Line 4 places the Dovecot SASL socket in /var/spool/postfix/private/auth, lines
+5-8 limit read+write permissions to user and group postfix only, and line 14
+provides plain and login as mechanisms for the Postfix SMTP server.
Proceed with the section "Enabling SASL authentication and authorization in the
Postfix SMTP server" to turn on and use SASL in the Postfix SMTP server.
independent from the DNS and native routines for host
name/address lookup.
+ Incorporate 3rd-party code such as dynamic_maps.
+
+ Support 3rd-party extension with /etc/postfix/postfix-files.d
+
Make been_here flag BH_FLAG_FOLD configurable for masochists.
Replace some redundant TLS_README sections with pointers
# For common configuration examples, see BASIC_CONFIGURATION_README
# and STANDARD_CONFIGURATION_README. To find these documents, use
# the command "postconf html_directory readme_directory", or go to
-# http://www.postfix.org/.
+# http://www.postfix.org/BASIC_CONFIGURATION_README.html etc.
#
# For best results, change no more than 2-3 parameters at a time,
# and test if Postfix still works after every change.
#
# Postfix master process configuration file. For details on the format
-# of the file, see the master(5) manual page (command: "man 5 master").
+# of the file, see the master(5) manual page (command: "man 5 master" or
+# on-line: http://www.postfix.org/master.5.html).
#
# Do not forget to execute "postfix reload" after editing this file.
#
<hr>
+<h2> Warning </h2>
+
+<p> Forward secrecy does not protect against active attacks such
+as forged DNS replies or forged TLS server certificates. If such
+attacks are a concern, then the SMTP client will need to authenticate
+the remote SMTP server in a sufficiently-secure manner. For example,
+by the fingerprint of the public key or certificate. Conventional
+PKI relies on many trusted parties and is easily subverted by a
+state-funded adversary. </p>
+
<h2> Background </h2>
<p> Postfix supports forward secrecy of TLS network communication
individual sessions may be infeasible given a sufficiently-strong
key agreement method. </p>
-<p> Forward secrecy protects network communication in the absence
-of active attacks, i.e. no forged DNS replies, and no forged TLS
-server certificates. If active attacks are a concern, then you will
-need to authenticate the remote SMTP server in a secure manner.
-For example, by the fingerprint of the public key or certificate.
-Conventional PKI relies on too many trusted parties. </p>
-
<p> Topics covered in this document: </p>
<ul>
<li><a href="#client_fs">Forward Secrecy in the Postfix SMTP Client</a>
-<li><a href="#test">How do I know that it works?</a>
+<li><a href="#quick-start">Getting started, quick and dirty</a>
+
+<li><a href="#test">How can I see that a connection has forward secrecy?</a>
+
+<li><a href="#ciphers"> What ciphers provide forward secrecy? </a>
+
+<li><a href="#status"> What do "Anonymous", "Untrusted", etc. in
+Postfix logging mean? </a>
<li><a href="#credits"> Credits </a>
<p> The key-exchange algorithms used for forward secrecy require
the TLS server to designate appropriate "parameters" consisting of a
mathematical "group" and an element of that group called a "generator".
-There are two flavors of "groups" that work with PFS: </p>
+Presently, there are two flavors of "groups" that work with PFS: </p>
<ul>
-<li> Prime field groups. The server needs to be configured with a
-suitably large prime and a corresponding "generator".
+<li> <p> <b> Prime-field groups (EDH):</b> The server needs to be
+configured with a suitably-large prime and a corresponding "generator".
+The acronym for forward secrecy over prime fields is EDH or Ephemeral
+Diffie-Hellman (sometimes also abbreviated as DHE). </p>
-<li> Elliptic curve groups. The server needs to be configured with
-a "named curve". These offer better security at lower computational
-cost than prime field groups, but are not as widely implemented.
+<li> <p> <b> Elliptic-curve groups (EECDH): </b> The server needs
+to be configured with a "named curve". These offer better security
+at lower computational cost than prime field groups, but are not
+as widely implemented. The acronym for the elliptic curve version
+is EECDH which is short for Ephemeral Elliptic Curve Diffie-Hellman.
+</p>
</ul>
-<p> The acronym for forward secrecy over prime fields is EDH or
-Ephemeral Diffie-Hellman (sometimes also abbreviated as DHE). The
-acronym for the elliptic curve version is EECDH which is short for
-Ephemeral Elliptic Curve Diffie-Hellman. </p>
-
<p> It is not essential to know what these are, but one does need
to know that OpenSSL only supports EECDH as of version 1.0.0. Thus
the configuration parameters related to Elliptic Curve forward secrecy
will likely cause interoperability issues with older Exchange servers
and is not recommended for now. </p>
-</ul>
-
<h3> EDH Server support </h3>
<p> Postfix ≥ 2.2 support 1024-bit-prime EDH out of the box,
(it is available only in OpenSSL development snapshots). </p>
<p> At some point Postfix will need to adjust to the new API for
-setting the elliptic curve options. Fortunately, when EECDH support
+setting the elliptic-curve options. Fortunately, when EECDH support
was added to Postfix, it introduced a layer of indirection: </p>
<blockquote>
<h2> <a name="client_fs">Forward Secrecy in the Postfix SMTP Client</a> </h2>
<p> The Postfix ≥ 2.2 SMTP client supports forward secrecy in
-its default configuration. If the remote SMTP server supports
-cipher suites with forward secrecy (and does not override the SMTP
-client cipher preference), then the traffic between the server and
-client will resist decryption even if the server's long-term
-authentication keys are <i>later</i> compromised. </p>
-
-<p> The default Postfix SMTP client cipher lists are correctly ordered
-to prefer EECDH and EDH cipher suites ahead of similar cipher suites
-that don't implement forward secrecy. Administrators are strongly
-discouraged from changing the cipher list definitions. It is likely
-safe to set "<a href="postconf.5.html#smtp_tls_ciphers">smtp_tls_ciphers</a> = medium" if you wish to disable the
-obsolete "export" and "low" grade ciphers even with opportunistic
-TLS. Setting a minimum strength does not change the preference
+its default configuration. No configuration changes are needed
+besides turning on elliptic-curve support with Postfix 2.6 and 2.7
+(see the <a href="#quick-start"> quick-start</a> section). If the
+remote SMTP server supports cipher suites with forward secrecy (and
+does not override the SMTP client's cipher preference), then the
+traffic between the server and client will resist decryption even
+if the server's long-term authentication keys are <i>later</i>
+compromised. </p>
+
+<p> The default Postfix SMTP client cipher lists are correctly
+ordered to prefer EECDH and EDH cipher suites ahead of similar
+cipher suites that don't implement forward secrecy. Administrators
+are strongly discouraged from changing the cipher list definitions.
+It is likely safe to set "<a href="postconf.5.html#smtp_tls_ciphers">smtp_tls_ciphers</a> = medium" if you wish
+to disable the obsolete "export" and "low" grade ciphers even with
+opportunistic TLS. Setting a minimum strength does not change the
+preference
order. Note that strengths higher than "medium" exclude Exchange
2003 and likely other widely used MTAs, thus "high" grade ciphers
should only be used on a case-by-case basis via the <a
<h2><a name="quick-start">Getting started, quick and dirty</a></h2>
-<p> At least one time as root (prime group generation can take a
+<ul>
+
+<li> <p> Postfix 2.6 and 2.7: Enable elliptic-curve support. This
+is the default with Postfix ≥ 2.8.
+
+<blockquote>
+<pre>
+/etc/postfix/<a href="postconf.5.html">main.cf</a>:
+ # Postfix 2.6 or 2.7 only. This is default with Postfix 2.8 and later.
+ <a href="postconf.5.html#smtpd_tls_eecdh_grade">smtpd_tls_eecdh_grade</a> = strong
+</pre>
+</blockquote>
+
+<li> <p> Optionally generate non-default EDH parameters for improved
+security against pre-computation attacks and for compatibility with
+Debian-patched EXIM SMTP clients (these require a minimum 2048-bit
+length for the non-export prime). The parameter files are not
+secret, after all these parameters are sent to all SMTP clients in
+the clear. Mode 0644 is fine. </p>
+
+<p> Execute as root (prime group generation can take a
few seconds to a few minutes): </p>
<blockquote>
</pre>
</blockquote>
-<p> Note: greater security against "pre-computation" attacks against
-EDH can be obtained by periodically regenerating the EDH parameters
-as above (an hourly or daily cron job running as root can automate
-this task). The parameter files are not secret, after all these are
-sent to all SMTP clients in the clear. Mode 0644 is fine. </p>
+<p> You can improve security against pre-computation attacks further
+by regenerating the EDH parameters periodically (an hourly or daily
+cron job running as root can automate this task). </p>
<p> Once the parameters are in place, update <a href="postconf.5.html">main.cf</a> as follows: </p>
<blockquote>
<pre>
/etc/postfix/<a href="postconf.5.html">main.cf</a>:
- # Postfix ≥ 2.6
- <a href="postconf.5.html#smtpd_tls_eecdh_grade">smtpd_tls_eecdh_grade</a> = strong
- # All versions of Postfix:
<a href="postconf.5.html#smtpd_tls_dh1024_param_file">smtpd_tls_dh1024_param_file</a> = ${<a href="postconf.5.html#config_directory">config_directory</a>}/dh2048.pem
<a href="postconf.5.html#smtpd_tls_dh512_param_file">smtpd_tls_dh512_param_file</a> = ${<a href="postconf.5.html#config_directory">config_directory</a>}/dh512.pem
</pre>
</pre>
</blockquote>
-<h2><a name="test">How do I know that it works? </a> </h2>
+</ul>
+
+<h2><a name="test">How can I see that a connection has forward
+secrecy? </a> </h2>
-<p> Postfix reports TLS connection information in several ways: </p>
+<p> Postfix can be configured to report information about the
+negotiated cipher, the corresponding key lengths, and the remote
+peer certificate or public-key verification status. </p>
<ul>
<li> <p> With "<a href="postconf.5.html#smtp_tls_loglevel">smtp_tls_loglevel</a> = 1" and "<a href="postconf.5.html#smtpd_tls_loglevel">smtpd_tls_loglevel</a> = 1",
-the Postfix SMTP client and server will log information about, among
-others, the remote peer certificate or public-key verification
-status, the negotiated cipher, and key lengths. The general logfile
-format is: </p>
+the Postfix SMTP client and server will log TLS connection information
+to the maillog file. The general logfile format is: </p>
<blockquote>
<pre>
-postfix/smtp[xxx]: Trusted TLS connection established to host.example.com[192.168.0.2]:25: TLSv1 with cipher XXX (YYY/ZZZ bits)
+postfix/smtp[<i>process-id</i>]: Untrusted TLS connection established
+to host.example.com[192.168.0.2]:25: TLSv1 with cipher <i>cipher-name</i>
+(<i>actual-key-size</i>/<i>raw-key-size</i> bits)
-postfix/smtpd[xxx]: Untrusted TLS connection established from host.example.com[192.168.0.2]: TLSv1 with cipher XXX (YYY/ZZZ bits)
+postfix/smtpd[<i>process-id</i>]: Anonymous TLS connection established
+from host.example.com[192.168.0.2]: TLSv1 with cipher <i>cipher-name</i>
+(<i>actual-key-size</i>/<i>raw-key-size</i> bits)
</pre>
</blockquote>
<li> <p> With "<a href="postconf.5.html#smtpd_tls_received_header">smtpd_tls_received_header</a> = yes", the Postfix SMTP
-server will record similar information in the Received: header in
-the form of comments (text inside parentheses). The general format
-is: </p>
+server will record TLS connection information in the Received:
+header in the form of comments (text inside parentheses). The general
+format depends on the <a href="postconf.5.html#smtpd_tls_ask_ccert">smtpd_tls_ask_ccert</a> setting:
<blockquote>
<pre>
Received: from host.example.com (host.example.com [192.168.0.2])
- (using TLSv1 with cipher XXX (YYY/ZZZ bits))
- (Client CN "host.example.com", Issuer "Wietse Venema" (not verified))
+ (using TLSv1 with cipher <i>cipher-name</i>
+ (<i>actual-key-size</i>/<i>raw-key-size</i> bits))
+ (Client CN "host.example.com", Issuer "John Doe" (not verified))
+
+Received: from host.example.com (host.example.com [192.168.0.2])
+ (using TLSv1 with cipher <i>cipher-name</i>
+ (<i>actual-key-size</i>/<i>raw-key-size</i> bits))
+ (No client certificate requested)
</pre>
</blockquote>
</ul>
-<p> There are dozens of ciphers that support forward secrecy. What
+<p> The next sections will explain what <i>cipher-name</i>,
+<i>key-size</i>, and peer verification status information to expect.
+</p>
+
+<h2><a name="ciphers"> What ciphers provide forward secrecy? </a> </h2>
+
+<p> There are dozens of ciphers that support forward secrecy. What
follows is the beginning of a list of 51 ciphers available with
-OpenSSL 1.0.1e: </p>
+OpenSSL 1.0.1e. The list is sorted in the default Postfix preference
+order. It excludes null ciphers that only authenticate and don't
+encrypt, together with export and low-grade ciphers whose encryption
+is too weak to offer meaningful secrecy. The first column shows the
+cipher name, and the second shows the key exchange method. </p>
<blockquote>
<pre>
</pre>
</blockquote>
+<p> To date, all ciphers that support forward secrecy have one of
+five values for the first component of their OpenSSL name: "AECDH",
+"ECDHE", "ADH", "EDH" or "DHE". Ciphers that don't implement forward
+secrecy have names that don't start with one of these prefixes.
+This pattern is likely to persist until some new key-exchange
+mechanism is invented that also supports forward secrecy. </p>
+
+<p> The actual key length and raw algorithm key length
+are generally the same with non-export ciphers, but may they
+differ for the legacy export ciphers where the actual key
+is artificially shortened. </p>
+
+<h2><a name="status"> What do "Anonymous", "Untrusted", etc. in
+Postfix logging mean? </a> </h2>
+
+<p> The verification levels below are subject to man-in-the-middle
+attacks to different degrees. If such attacks are a concern, then
+the SMTP client will need to authenticate the remote SMTP server
+in a sufficiently-secure manner. For example, by the fingerprint
+of the public key or certificate. Remember that conventional PKI
+relies on many trusted parties and is easily subverted by a
+state-funded adversary. </p>
+
+<dl>
+
+<dt><b>Anonymous</b> (no peer certificate)</dt>
+
+<dd> <p> <b> Postfix SMTP client:</b> With opportunistic TLS (the "may" security level) the Postfix
+SMTP client does not verify any information in the peer certificate.
+In this case it enables and prefers anonymous cipher suites in which
+the remote SMTP server does not present a certificate (these ciphers
+offer forward secrecy of necessity). When the remote SMTP server
+also supports anonymous TLS, and agrees to such a cipher suite, the
+verification status will be logged as "Anonymous". </p> </dd>
+
+<dd> <p> <b> Postfix SMTP server:</b> This is by far most common,
+as client certificates are optional, and the Postfix SMTP server
+does not request client certificates by default (see <a href="postconf.5.html#smtpd_tls_ask_ccert">smtpd_tls_ask_ccert</a>).
+Even when client certificates are requested, the remote SMTP client
+might not send a certificate. Unlike the Postfix SMTP client, the
+Postfix SMTP server "anonymous" verification status does not imply
+that the cipher suite is anonymous, which corresponds to the
+<i>server</i> not sending a certificate. </p> </dd>
+
+<dt><b>Untrusted</b> (peer certificate not signed by trusted CA)</dt>
+
+<dd>
+
+<p> <b> Postfix SMTP client:</b> The remote SMTP server presented
+a certificate, but the Postfix SMTP client was unable to check the
+issuing CA signature. With opportunistic TLS this is common with
+remote SMTP servers that don't support anonymous cipher suites.
+</p>
+
+<p> <b> Postfix SMTP server:</b> The remote SMTP client presented
+a certificate, but the Postfix SMTP server was unable to check the
+issuing CA signature. This can happen when the server is configured
+to request client certificates (see <a href="postconf.5.html#smtpd_tls_ask_ccert">smtpd_tls_ask_ccert</a>). </p>
+
+</dd>
+
+<dt><b>Trusted</b> (peer certificate signed by trusted CA, unverified
+peer name)</dt>
+
+<dd>
+
+<p> <b> Postfix SMTP client:</b> The remote SMTP server's certificate
+was signed by a CA that the Postfix SMTP client trusts, but either
+the client was not configured to verify the destination server name
+against the certificate, or the server certificate did not contain
+any matching names. This is common with opportunistic TLS
+(<a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a> is "may" or else "dane" with no usable
+TLSA DNS records) when the Postfix SMTP client's trusted CAs can
+verify the authenticity of the remote SMTP server's certificate,
+but the client is not configured or unable to verify the server
+name. </p>
+
+<p> <b> Postfix SMTP server:</b> The remote SMTP client certificate
+was signed by a CA that the Postfix SMTP server trusts. The Postfix
+SMTP server never verifies the remote SMTP client name against the
+names in the certificate. Since the client chooses to connect to
+the server, the Postfix SMTP server has no expectation of a particular
+client hostname. </p>
+
+</dd>
+
+<dt><b>Verified</b> (peer certificate signed by trusted CA, verified
+peer name)</dt>
+
+<dd>
+
+<p> <b> Postfix SMTP client:</b> The remote SMTP server's certificate
+was signed by a CA that the Postfix SMTP client trusts, and it
+matches one of the expected server names. This implies that the
+Postfix SMTP client enforced verification for the destination server
+name, otherwise the verification status would have been just
+"Trusted". </p>
+
+<p> <b> Postfix SMTP server:</b> The status is never "Verified",
+as the Postfix SMTP server never verifies the remote SMTP client
+name against the names in the certificate. </p>
+
+</dd>
+
+</dl>
+
<h2><a name="credits">Credits </a> </h2>
<ul>
-<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN"
+X<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<head>
<h4><a name="server_dovecot_comm">Postfix to Dovecot SASL communication</a></h4>
<p> Communication between the Postfix SMTP server and Dovecot SASL
-happens over a UNIX-domain socket or over a TCP socket. Dovecot 1
-supports UNIX-domain socket communication only. </p>
+happens over a UNIX-domain socket or over a TCP socket. We will
+be using a UNIX-domain socket for better privacy. </p>
-<h5>UNIX-domain socket communication</h5>
-
-<p> The socket
-pathname and the list of mechanisms offered to Postfix need to be
-specified on the Dovecot server side in <code>dovecot.conf</code>.
-</p>
-
-<p> The following example assumes that the Postfix queue is under
-<code>/var/spool/postfix/</code>. </p>
-
-<p> Note: the example uses Dovecot 1 syntax, See <a href="http://www.dovecot.org/">http://www.dovecot.org/</a>
-for newer syntax. </p>
+<p> The following fragment for Dovecot version 2 assumes that the
+Postfix queue is under <code>/var/spool/postfix/</code>. </p>
<blockquote>
<pre>
- 1 /etc/dovecot.conf:
- 2 auth default {
- 3 mechanisms = plain login
- 4 passdb pam {
- 5 }
- 6 userdb passwd {
- 7 }
- 8 socket listen {
- 9 client {
-10 path = /var/spool/postfix/private/auth
-11 mode = 0660
-12 user = postfix
-13 group = postfix
-14 }
-15 }
-16 }
+ 1 conf.d/10-master.conf:
+ 2 service auth {
+ 3 ...
+ 4 unix_listener /var/spool/postfix/private/auth {
+ 5 mode = 0660
+ 6 # Assuming the default Postfix user and group
+ 7 user = postfix
+ 8 group = postfix
+ 9 }
+10 ...
+11 }
+12
+13 conf.d/10-auth.conf
+14 auth_mechanisms = plain login
</pre>
</blockquote>
-<p> Line 3 provides <code>plain</code> and <code>login</code> as
-mechanisms for the Postfix SMTP server, line 10 places the Dovecot
-SASL socket in <code>/var/spool/postfix/private/auth</code>, and
-lines 11-13 limit read+write permissions to user and group
-<code>postfix</code> only. </p>
-
-<p> Proceed with the section "<a href="#server_sasl_enable">Enabling
-SASL authentication and authorization in the Postfix SMTP server</a>"
-to turn on and use SASL in the Postfix SMTP server. </p>
-
-<h5>TCP socket communication</h5>
-
-<p> The TCP port and the list of mechanisms offered to Postfix need
-to be specified on the Dovecot server side in <code>10-auth.conf</code>
-and <code>10-master.conf</code>. </p>
-
-<p> The following examples assume that Postfix should communicate
-with Dovecot on TCP port 12345. </p>
-
-<p> Note: the examples use Dovecot 1 syntax, See <a href="http://www.dovecot.org/">http://www.dovecot.org/</a>
-for newer syntax. </p>
-
-<blockquote>
-<pre>
-1 /etc/dovecot/conf.d/10-auth.conf:
-2 auth_mechanisms = plain login
-</pre>
-</blockquote>
-
-<p> Line 2 provides plain and login as mechanisms for the Postfix
-SMTP server. </p>
-
-<blockquote>
-<pre>
-1 /etc/dovecot/conf.d/10-master.conf:
-2 service auth {
-3 unix_listener auth-userdb {
-4 }
-5 inet_listener {
-6 port = 12345
-7 }
-8 }
-</pre>
-</blockquote>
-
-<p> Line 5 creates a new TCP socket and line 6 specifies port 12345
-where Dovecot SASL should wait for Postfix authentication requests.
-</p>
+<p> Line 4 places the Dovecot SASL socket in
+<code>/var/spool/postfix/private/auth</code>, lines 5-8 limit
+read+write permissions to user and group <code>postfix</code> only,
+and line 14 provides <code>plain</code> and <code>login</code> as
+mechanisms for the Postfix SMTP server. </p>
<p> Proceed with the section "<a href="#server_sasl_enable">Enabling
SASL authentication and authorization in the Postfix SMTP server</a>"
</pre>
+</DD>
+
+<DT><b><a name="smtpd_sasl_service">smtpd_sasl_service</a>
+(default: smtp)</b></DT><DD>
+
+<p> The service name that is passed to the SASL plug-in that is
+selected with <b><a href="postconf.5.html#smtpd_sasl_type">smtpd_sasl_type</a></b> and <b><a href="postconf.5.html#smtpd_sasl_path">smtpd_sasl_path</a></b>.
+</p>
+
+<p> This feature is available in Postfix 2.11 and later. Prior
+versions behave as if "<b>smtp</b>" is specified. </p>
+
+
</DD>
<DT><b><a name="smtpd_sasl_tls_security_options">smtpd_sasl_tls_security_options</a>
Search path for Cyrus SASL application configuration files, cur-
rently used only to locate the $<a href="postconf.5.html#smtpd_sasl_path">smtpd_sasl_path</a>.conf file.
+ Available in Postfix version 2.11 and later:
+
+ <b>smtpd_sasl_service (smtp)</b>
+ The service name that is passed to the SASL plug-in that is
+ selected with <b><a href="postconf.5.html#smtpd_sasl_type">smtpd_sasl_type</a></b> and <b><a href="postconf.5.html#smtpd_sasl_path">smtpd_sasl_path</a></b>.
+
<b>STARTTLS SUPPORT CONTROLS</b>
- Detailed information about STARTTLS configuration may be found in the
+ Detailed information about STARTTLS configuration may be found in the
<a href="TLS_README.html">TLS_README</a> document.
<b><a href="postconf.5.html#smtpd_tls_security_level">smtpd_tls_security_level</a> (empty)</b>
- The SMTP TLS security level for the Postfix SMTP server; when a
+ The SMTP TLS security level for the Postfix SMTP server; when a
non-empty value is specified, this overrides the obsolete param-
eters <a href="postconf.5.html#smtpd_use_tls">smtpd_use_tls</a> and <a href="postconf.5.html#smtpd_enforce_tls">smtpd_enforce_tls</a>.
<b><a href="postconf.5.html#smtpd_sasl_tls_security_options">smtpd_sasl_tls_security_options</a> ($<a href="postconf.5.html#smtpd_sasl_security_options">smtpd_sasl_security_options</a>)</b>
- The SASL authentication security options that the Postfix SMTP
+ The SASL authentication security options that the Postfix SMTP
server uses for TLS encrypted SMTP sessions.
<b><a href="postconf.5.html#smtpd_starttls_timeout">smtpd_starttls_timeout</a> (see 'postconf -d' output)</b>
during TLS startup and shutdown handshake procedures.
<b><a href="postconf.5.html#smtpd_tls_CAfile">smtpd_tls_CAfile</a> (empty)</b>
- A file containing (PEM format) CA certificates of root CAs
+ A file containing (PEM format) CA certificates of root CAs
trusted to sign either remote SMTP client certificates or inter-
mediate CA certificates.
<b><a href="postconf.5.html#smtpd_tls_CApath">smtpd_tls_CApath</a> (empty)</b>
- A directory containing (PEM format) CA certificates of root CAs
+ A directory containing (PEM format) CA certificates of root CAs
trusted to sign either remote SMTP client certificates or inter-
mediate CA certificates.
<b><a href="postconf.5.html#smtpd_tls_always_issue_session_ids">smtpd_tls_always_issue_session_ids</a> (yes)</b>
- Force the Postfix SMTP server to issue a TLS session id, even
- when
TLS session caching is turned off (<a href="postconf.5.html#smtpd_tls_session_cache_database">smtpd_tls_ses</a>-
+ Force the Postfix SMTP server to issue a TLS session id, even
+ when
TLS session caching is turned off (<a href="postconf.5.html#smtpd_tls_session_cache_database">smtpd_tls_ses</a>-
<a href="postconf.5.html#smtpd_tls_session_cache_database">sion_cache_database</a> is empty).
<b><a href="postconf.5.html#smtpd_tls_ask_ccert">smtpd_tls_ask_ccert</a> (no)</b>
Ask a remote SMTP client for a client certificate.
<b><a href="postconf.5.html#smtpd_tls_auth_only">smtpd_tls_auth_only</a> (no)</b>
- When TLS encryption is optional in the Postfix SMTP server, do
+ When TLS encryption is optional in the Postfix SMTP server, do
not announce or accept SASL authentication over unencrypted con-
nections.
File with the Postfix SMTP server RSA certificate in PEM format.
<b><a href="postconf.5.html#smtpd_tls_exclude_ciphers">smtpd_tls_exclude_ciphers</a> (empty)</b>
- List of ciphers or cipher types to exclude from the SMTP server
+ List of ciphers or cipher types to exclude from the SMTP server
cipher list at all TLS security levels.
<b><a href="postconf.5.html#smtpd_tls_dcert_file">smtpd_tls_dcert_file</a> (empty)</b>
File with the Postfix SMTP server DSA certificate in PEM format.
<b><a href="postconf.5.html#smtpd_tls_dh1024_param_file">smtpd_tls_dh1024_param_file</a> (empty)</b>
- File with DH parameters that the Postfix SMTP server should use
+ File with DH parameters that the Postfix SMTP server should use
with EDH ciphers.
<b><a href="postconf.5.html#smtpd_tls_dh512_param_file">smtpd_tls_dh512_param_file</a> (empty)</b>
- File with DH parameters that the Postfix SMTP server should use
+ File with DH parameters that the Postfix SMTP server should use
with EDH ciphers.
<b><a href="postconf.5.html#smtpd_tls_dkey_file">smtpd_tls_dkey_file</a> ($<a href="postconf.5.html#smtpd_tls_dcert_file">smtpd_tls_dcert_file</a>)</b>
Enable additional Postfix SMTP server logging of TLS activity.
<b><a href="postconf.5.html#smtpd_tls_mandatory_ciphers">smtpd_tls_mandatory_ciphers</a> (medium)</b>
- The minimum TLS cipher grade that the Postfix SMTP server will
+ The minimum TLS cipher grade that the Postfix SMTP server will
use with mandatory TLS encryption.
<b><a href="postconf.5.html#smtpd_tls_mandatory_exclude_ciphers">smtpd_tls_mandatory_exclude_ciphers</a> (empty)</b>
- Additional list of ciphers or cipher types to exclude from the
- Postfix SMTP server cipher list at mandatory TLS security lev-
+ Additional list of ciphers or cipher types to exclude from the
+ Postfix SMTP server cipher list at mandatory TLS security lev-
els.
<b><a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> (!SSLv2)</b>
- The SSL/TLS protocols accepted by the Postfix SMTP server with
+ The SSL/TLS protocols accepted by the Postfix SMTP server with
mandatory TLS encryption.
<b><a href="postconf.5.html#smtpd_tls_received_header">smtpd_tls_received_header</a> (no)</b>
Request that the Postfix SMTP server produces Received: message
- headers that include information about the protocol and cipher
- used, as well as the remote SMTP client CommonName and client
+ headers that include information about the protocol and cipher
+ used, as well as the remote SMTP client CommonName and client
certificate issuer CommonName.
<b><a href="postconf.5.html#smtpd_tls_req_ccert">smtpd_tls_req_ccert</a> (no)</b>
- With mandatory TLS encryption, require a trusted remote SMTP
+ With mandatory TLS encryption, require a trusted remote SMTP
client certificate in order to allow TLS connections to proceed.
<b><a href="postconf.5.html#smtpd_tls_wrappermode">smtpd_tls_wrappermode</a> (no)</b>
- Run the Postfix SMTP server in the non-standard "wrapper" mode,
+ Run the Postfix SMTP server in the non-standard "wrapper" mode,
instead of using the STARTTLS command.
<b><a href="postconf.5.html#tls_daemon_random_bytes">tls_daemon_random_bytes</a> (32)</b>
- The
number of pseudo-random bytes that an <a href="smtp.8.html"><b>smtp</b>(8)</a> or <a href="smtpd.8.html"><b>smtpd</b>(8)</a>
- process requests from the <a href="tlsmgr.8.html"><b>tlsmgr</b>(8)</a> server in order to seed its
+ The
number of pseudo-random bytes that an <a href="smtp.8.html"><b>smtp</b>(8)</a> or <a href="smtpd.8.html"><b>smtpd</b>(8)</a>
+ process requests from the <a href="tlsmgr.8.html"><b>tlsmgr</b>(8)</a> server in order to seed its
internal pseudo random number generator (PRNG).
<b><a href="postconf.5.html#tls_high_cipherlist">tls_high_cipherlist</a> (ALL:!EXPORT:!LOW:!MEDIUM:+RC4:@STRENGTH)</b>
The OpenSSL cipherlist for "EXPORT" or higher grade ciphers.
<b><a href="postconf.5.html#tls_null_cipherlist">tls_null_cipherlist</a> (eNULL:!aNULL)</b>
- The OpenSSL cipherlist for "NULL" grade ciphers that provide
+ The OpenSSL cipherlist for "NULL" grade ciphers that provide
authentication without encryption.
Available in Postfix version 2.5 and later:
<b><a href="postconf.5.html#smtpd_tls_fingerprint_digest">smtpd_tls_fingerprint_digest</a> (md5)</b>
- The message digest algorithm to construct remote SMTP client-
+ The message digest algorithm to construct remote SMTP client-
certificate fingerprints or public key fingerprints (Postfix 2.9
and later) for <b><a href="postconf.5.html#check_ccert_access">check_ccert_access</a></b> and <b><a href="postconf.5.html#permit_tls_clientcerts">permit_tls_clientcerts</a></b>.
Available in Postfix version 2.6 and later:
<b><a href="postconf.5.html#smtpd_tls_protocols">smtpd_tls_protocols</a> (empty)</b>
- List of TLS protocols that the Postfix SMTP server will exclude
+ List of TLS protocols that the Postfix SMTP server will exclude
or include with opportunistic TLS encryption.
<b><a href="postconf.5.html#smtpd_tls_ciphers">smtpd_tls_ciphers</a> (export)</b>
- The minimum TLS cipher grade that the Postfix SMTP server will
+ The minimum TLS cipher grade that the Postfix SMTP server will
use with opportunistic TLS encryption.
<b><a href="postconf.5.html#smtpd_tls_eccert_file">smtpd_tls_eccert_file</a> (empty)</b>
- File with the Postfix SMTP server ECDSA certificate in PEM for-
+ File with the Postfix SMTP server ECDSA certificate in PEM for-
mat.
<b><a href="postconf.5.html#smtpd_tls_eckey_file">smtpd_tls_eckey_file</a> ($<a href="postconf.5.html#smtpd_tls_eccert_file">smtpd_tls_eccert_file</a>)</b>
- File with the Postfix SMTP server ECDSA private key in PEM for-
+ File with the Postfix SMTP server ECDSA private key in PEM for-
mat.
<b><a href="postconf.5.html#smtpd_tls_eecdh_grade">smtpd_tls_eecdh_grade</a> (see 'postconf -d' output)</b>
- The Postfix SMTP server security grade for ephemeral elliptic-
+ The Postfix SMTP server security grade for ephemeral elliptic-
curve Diffie-Hellman (EECDH) key exchange.
<b><a href="postconf.5.html#tls_eecdh_strong_curve">tls_eecdh_strong_curve</a> (prime256v1)</b>
- The elliptic curve used by the Postfix SMTP server for sensibly
+ The elliptic curve used by the Postfix SMTP server for sensibly
strong ephemeral ECDH key exchange.
<b><a href="postconf.5.html#tls_eecdh_ultra_curve">tls_eecdh_ultra_curve</a> (secp384r1)</b>
<b><a href="postconf.5.html#tls_preempt_cipherlist">tls_preempt_cipherlist</a> (no)</b>
With SSLv3 and later, use the Postfix SMTP server's cipher pref-
- erence order instead of the remote client's cipher preference
+ erence order instead of the remote client's cipher preference
order.
<b><a href="postconf.5.html#tls_disable_workarounds">tls_disable_workarounds</a> (see 'postconf -d' output)</b>
The name of the <a href="tlsmgr.8.html"><b>tlsmgr</b>(8)</a> service entry in <a href="master.5.html">master.cf</a>.
<b>OBSOLETE STARTTLS CONTROLS</b>
- The following configuration parameters exist for compatibility with
- Postfix versions before 2.3. Support for these will be removed in a
+ The following configuration parameters exist for compatibility with
+ Postfix versions before 2.3. Support for these will be removed in a
future release.
<b><a href="postconf.5.html#smtpd_use_tls">smtpd_use_tls</a> (no)</b>
- Opportunistic TLS: announce STARTTLS support to remote SMTP
+ Opportunistic TLS: announce STARTTLS support to remote SMTP
clients, but do not require that clients use TLS encryption.
<b><a href="postconf.5.html#smtpd_enforce_tls">smtpd_enforce_tls</a> (no)</b>
and require that clients use TLS encryption.
<b><a href="postconf.5.html#smtpd_tls_cipherlist">smtpd_tls_cipherlist</a> (empty)</b>
- Obsolete Postfix < 2.3 control for the Postfix SMTP server TLS
+ Obsolete Postfix < 2.3 control for the Postfix SMTP server TLS
cipher list.
<b>VERP SUPPORT CONTROLS</b>
- With VERP style delivery, each recipient of a message receives a cus-
- tomized copy of the message with his/her own recipient address encoded
+ With VERP style delivery, each recipient of a message receives a cus-
+ tomized copy of the message with his/her own recipient address encoded
in the envelope sender address. The <a href="VERP_README.html">VERP_README</a> file describes config-
- uration and operation details of Postfix support for variable envelope
- return path addresses. VERP style delivery is requested with the SMTP
- XVERP command or with the "sendmail -V" command-line option and is
+ uration and operation details of Postfix support for variable envelope
+ return path addresses. VERP style delivery is requested with the SMTP
+ XVERP command or with the "sendmail -V" command-line option and is
available in Postfix version 1.1 and later.
<b><a href="postconf.5.html#default_verp_delimiters">default_verp_delimiters</a> (+=)</b>
The two default VERP delimiter characters.
<b><a href="postconf.5.html#verp_delimiter_filter">verp_delimiter_filter</a> (-=+)</b>
- The characters Postfix accepts as VERP delimiter characters on
+ The characters Postfix accepts as VERP delimiter characters on
the Postfix <a href="sendmail.1.html"><b>sendmail</b>(1)</a> command line and in SMTP commands.
Available in Postfix version 1.1 and 2.0:
<b><a href="postconf.5.html#authorized_verp_clients">authorized_verp_clients</a> ($<a href="postconf.5.html#mynetworks">mynetworks</a>)</b>
- What remote SMTP clients are allowed to specify the XVERP com-
+ What remote SMTP clients are allowed to specify the XVERP com-
mand.
Available in Postfix version 2.1 and later:
<b><a href="postconf.5.html#smtpd_authorized_verp_clients">smtpd_authorized_verp_clients</a> ($<a href="postconf.5.html#authorized_verp_clients">authorized_verp_clients</a>)</b>
- What remote SMTP clients are allowed to specify the XVERP com-
+ What remote SMTP clients are allowed to specify the XVERP com-
mand.
<b>TROUBLE SHOOTING CONTROLS</b>
- The <a href="DEBUG_README.html">DEBUG_README</a> document describes how to debug parts of the Postfix
- mail system. The methods vary from making the software log a lot of
+ The <a href="DEBUG_README.html">DEBUG_README</a> document describes how to debug parts of the Postfix
+ mail system. The methods vary from making the software log a lot of
detail, to running some daemon processes under control of a call tracer
or debugger.
<b><a href="postconf.5.html#debug_peer_level">debug_peer_level</a> (2)</b>
- The increment in verbose logging level when a remote client or
+ The increment in verbose logging level when a remote client or
server matches a pattern in the <a href="postconf.5.html#debug_peer_list">debug_peer_list</a> parameter.
<b><a href="postconf.5.html#debug_peer_list">debug_peer_list</a> (empty)</b>
- Optional list of remote client or server hostname or network
+ Optional list of remote client or server hostname or network
address patterns that cause the verbose logging level to
increase by the amount specified in $<a href="postconf.5.html#debug_peer_level">debug_peer_level</a>.
<b><a href="postconf.5.html#error_notice_recipient">error_notice_recipient</a> (postmaster)</b>
- The recipient of postmaster notifications about mail delivery
+ The recipient of postmaster notifications about mail delivery
problems that are caused by policy, resource, software or proto-
col errors.
The list of error classes that are reported to the postmaster.
<b><a href="postconf.5.html#smtpd_reject_footer">smtpd_reject_footer</a> (empty)</b>
- Optional information that is appended after each Postfix SMTP
+ Optional information that is appended after each Postfix SMTP
server 4XX or 5XX response.
<b><a href="postconf.5.html#soft_bounce">soft_bounce</a> (no)</b>
- Safety net to keep mail queued that would otherwise be returned
+ Safety net to keep mail queued that would otherwise be returned
to the sender.
Available in Postfix version 2.1 and later:
Available in Postfix version 2.10 and later:
<b><a href="postconf.5.html#smtpd_log_access_permit_actions">smtpd_log_access_permit_actions</a> (empty)</b>
- Enable logging of the named "permit" actions in SMTP server
- access lists (by default, the SMTP server logs "reject" actions
+ Enable logging of the named "permit" actions in SMTP server
+ access lists (by default, the SMTP server logs "reject" actions
but not "permit" actions).
<b>KNOWN VERSUS UNKNOWN RECIPIENT CONTROLS</b>
- As of Postfix version 2.0, the SMTP server rejects mail for unknown
+ As of Postfix version 2.0, the SMTP server rejects mail for unknown
recipients. This prevents the mail queue from clogging up with undeliv-
- erable MAILER-DAEMON messages. Additional information on this topic is
+ erable MAILER-DAEMON messages. Additional information on this topic is
in the <a href="LOCAL_RECIPIENT_README.html">LOCAL_RECIPIENT_README</a> and <a href="ADDRESS_CLASS_README.html">ADDRESS_CLASS_README</a> documents.
<b><a href="postconf.5.html#show_user_unknown_table_name">show_user_unknown_table_name</a> (yes)</b>
- Display the name of the recipient table in the "User unknown"
+ Display the name of the recipient table in the "User unknown"
responses.
<b><a href="postconf.5.html#canonical_maps">canonical_maps</a> (empty)</b>
- Optional address mapping lookup tables for message headers and
+ Optional address mapping lookup tables for message headers and
envelopes.
<b><a href="postconf.5.html#recipient_canonical_maps">recipient_canonical_maps</a> (empty)</b>
- Optional address mapping lookup tables for envelope and header
+ Optional address mapping lookup tables for envelope and header
recipient addresses.
Parameters concerning known/unknown local recipients:
<b><a href="postconf.5.html#mydestination">mydestination</a> ($<a href="postconf.5.html#myhostname">myhostname</a>, localhost.$<a href="postconf.5.html#mydomain">mydomain</a>, localhost)</b>
- The
list of domains that are delivered via the $<a href="postconf.5.html#local_transport">local_transport</a>
+ The
list of domains that are delivered via the $<a href="postconf.5.html#local_transport">local_transport</a>
mail delivery transport.
<b><a href="postconf.5.html#inet_interfaces">inet_interfaces</a> (all)</b>
- The network interface addresses that this mail system receives
+ The network interface addresses that this mail system receives
mail on.
<b><a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a> (empty)</b>
- The network interface addresses that this mail system receives
+ The network interface addresses that this mail system receives
mail on by way of a proxy or network address translation unit.
<b><a href="postconf.5.html#inet_protocols">inet_protocols</a> (all)</b>
- The Internet protocols Postfix will attempt to use when making
+ The Internet protocols Postfix will attempt to use when making
or accepting connections.
<b><a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> (<a href="proxymap.8.html">proxy</a>:unix:passwd.byname $<a href="postconf.5.html#alias_maps">alias_maps</a>)</b>
Lookup tables with all names or addresses of local recipients: a
- recipient
address is local when its domain matches $<a href="postconf.5.html#mydestination">mydestina</a>-
+ recipient
address is local when its domain matches $<a href="postconf.5.html#mydestination">mydestina</a>-
<a href="postconf.5.html#mydestination">tion</a>, $<a href="postconf.5.html#inet_interfaces">inet_interfaces</a> or $<a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a>.
<b><a href="postconf.5.html#unknown_local_recipient_reject_code">unknown_local_recipient_reject_code</a> (550)</b>
The numerical Postfix SMTP server response code when a recipient
- address is local, and $<a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> specifies a list of
+ address is local, and $<a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> specifies a list of
lookup tables that does not match the recipient.
Parameters concerning known/unknown recipients of relay destinations:
<b><a href="postconf.5.html#relay_domains">relay_domains</a> ($<a href="postconf.5.html#mydestination">mydestination</a>)</b>
- What destination domains (and subdomains thereof) this system
+ What destination domains (and subdomains thereof) this system
will relay mail to.
<b><a href="postconf.5.html#relay_recipient_maps">relay_recipient_maps</a> (empty)</b>
- Optional lookup tables with all valid addresses in the domains
+ Optional lookup tables with all valid addresses in the domains
that match $<a href="postconf.5.html#relay_domains">relay_domains</a>.
<b><a href="postconf.5.html#unknown_relay_recipient_reject_code">unknown_relay_recipient_reject_code</a> (550)</b>
- The numerical Postfix SMTP server reply code when a recipient
- address matches $<a href="postconf.5.html#relay_domains">relay_domains</a>, and <a href="postconf.5.html#relay_recipient_maps">relay_recipient_maps</a> speci-
- fies a list of lookup tables that does not match the recipient
+ The numerical Postfix SMTP server reply code when a recipient
+ address matches $<a href="postconf.5.html#relay_domains">relay_domains</a>, and <a href="postconf.5.html#relay_recipient_maps">relay_recipient_maps</a> speci-
+ fies a list of lookup tables that does not match the recipient
address.
- Parameters concerning known/unknown recipients in virtual alias
+ Parameters concerning known/unknown recipients in virtual alias
domains:
<b><a href="postconf.5.html#virtual_alias_domains">virtual_alias_domains</a> ($<a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a>)</b>
- Postfix is final destination for the specified list of virtual
- alias domains, that is, domains for which all addresses are
+ Postfix is final destination for the specified list of virtual
+ alias domains, that is, domains for which all addresses are
aliased to addresses in other local or remote domains.
<b><a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a> ($<a href="postconf.5.html#virtual_maps">virtual_maps</a>)</b>
- Optional lookup tables that alias specific mail addresses or
+ Optional lookup tables that alias specific mail addresses or
domains to other local or remote address.
<b><a href="postconf.5.html#unknown_virtual_alias_reject_code">unknown_virtual_alias_reject_code</a> (550)</b>
- The Postfix SMTP server reply code when a recipient address
- matches $<a href="postconf.5.html#virtual_alias_domains">virtual_alias_domains</a>, and $<a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a> speci-
- fies a list of lookup tables that does not match the recipient
+ The Postfix SMTP server reply code when a recipient address
+ matches $<a href="postconf.5.html#virtual_alias_domains">virtual_alias_domains</a>, and $<a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a> speci-
+ fies a list of lookup tables that does not match the recipient
address.
Parameters concerning known/unknown recipients in virtual mailbox
domains:
<b><a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a> ($<a href="postconf.5.html#virtual_mailbox_maps">virtual_mailbox_maps</a>)</b>
- Postfix is final destination for the specified list of domains;
- mail is delivered via the $<a href="postconf.5.html#virtual_transport">virtual_transport</a> mail delivery
+ Postfix is final destination for the specified list of domains;
+ mail is delivered via the $<a href="postconf.5.html#virtual_transport">virtual_transport</a> mail delivery
transport.
<b><a href="postconf.5.html#virtual_mailbox_maps">virtual_mailbox_maps</a> (empty)</b>
- Optional lookup tables with all valid addresses in the domains
+ Optional lookup tables with all valid addresses in the domains
that match $<a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a>.
<b><a href="postconf.5.html#unknown_virtual_mailbox_reject_code">unknown_virtual_mailbox_reject_code</a> (550)</b>
- The Postfix SMTP server reply code when a recipient address
- matches
$<a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a>, and $<a href="postconf.5.html#virtual_mailbox_maps">virtual_mailbox_maps</a>
+ The Postfix SMTP server reply code when a recipient address
+ matches
$<a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a>, and $<a href="postconf.5.html#virtual_mailbox_maps">virtual_mailbox_maps</a>
specifies a list of lookup tables that does not match the recip-
ient address.
control client request rates.
<b><a href="postconf.5.html#line_length_limit">line_length_limit</a> (2048)</b>
- Upon input, long lines are chopped up into pieces of at most
+ Upon input, long lines are chopped up into pieces of at most
this length; upon delivery, long lines are reconstructed.
<b><a href="postconf.5.html#queue_minfree">queue_minfree</a> (0)</b>
tem that is needed to receive mail.
<b><a href="postconf.5.html#message_size_limit">message_size_limit</a> (10240000)</b>
- The maximal size in bytes of a message, including envelope
+ The maximal size in bytes of a message, including envelope
information.
<b><a href="postconf.5.html#smtpd_recipient_limit">smtpd_recipient_limit</a> (1000)</b>
- The maximal number of recipients that the Postfix SMTP server
+ The maximal number of recipients that the Postfix SMTP server
accepts per message delivery request.
<b><a href="postconf.5.html#smtpd_timeout">smtpd_timeout</a> (normal: 300s, overload: 10s)</b>
- The time limit for sending a Postfix SMTP server response and
+ The time limit for sending a Postfix SMTP server response and
for receiving a remote SMTP client request.
<b><a href="postconf.5.html#smtpd_history_flush_threshold">smtpd_history_flush_threshold</a> (100)</b>
- The maximal number of lines in the Postfix SMTP server command
- history before it is flushed upon receipt of EHLO, RSET, or end
+ The maximal number of lines in the Postfix SMTP server command
+ history before it is flushed upon receipt of EHLO, RSET, or end
of DATA.
Available in Postfix version 2.3 and later:
<b><a href="postconf.5.html#smtpd_peername_lookup">smtpd_peername_lookup</a> (yes)</b>
- Attempt to look up the remote SMTP client hostname, and verify
+ Attempt to look up the remote SMTP client hostname, and verify
that the name matches the client IP address.
The per SMTP client connection count and request rate limits are imple-
- mented in co-operation with the <a href="anvil.8.html"><b>anvil</b>(8)</a> service, and are available in
+ mented in co-operation with the <a href="anvil.8.html"><b>anvil</b>(8)</a> service, and are available in
Postfix version 2.2 and later.
<b><a href="postconf.5.html#smtpd_client_connection_count_limit">smtpd_client_connection_count_limit</a> (50)</b>
- How many simultaneous connections any client is allowed to make
+ How many simultaneous connections any client is allowed to make
to this service.
<b><a href="postconf.5.html#smtpd_client_connection_rate_limit">smtpd_client_connection_rate_limit</a> (0)</b>
- The maximal number of connection attempts any client is allowed
+ The maximal number of connection attempts any client is allowed
to make to this service per time unit.
<b><a href="postconf.5.html#smtpd_client_message_rate_limit">smtpd_client_message_rate_limit</a> (0)</b>
- The maximal number of message delivery requests that any client
- is allowed to make to this service per time unit, regardless of
+ The maximal number of message delivery requests that any client
+ is allowed to make to this service per time unit, regardless of
whether or not Postfix actually accepts those messages.
<b><a href="postconf.5.html#smtpd_client_recipient_rate_limit">smtpd_client_recipient_rate_limit</a> (0)</b>
- The maximal number of recipient addresses that any client is
- allowed to send to this service per time unit, regardless of
+ The maximal number of recipient addresses that any client is
+ allowed to send to this service per time unit, regardless of
whether or not Postfix actually accepts those recipients.
<b><a href="postconf.5.html#smtpd_client_event_limit_exceptions">smtpd_client_event_limit_exceptions</a> ($<a href="postconf.5.html#mynetworks">mynetworks</a>)</b>
- Clients that are excluded from smtpd_client_*_count/rate_limit
+ Clients that are excluded from smtpd_client_*_count/rate_limit
restrictions.
Available in Postfix version 2.3 and later:
<b><a href="postconf.5.html#smtpd_client_new_tls_session_rate_limit">smtpd_client_new_tls_session_rate_limit</a> (0)</b>
- The maximal number of new (i.e., uncached) TLS sessions that a
+ The maximal number of new (i.e., uncached) TLS sessions that a
remote SMTP client is allowed to negotiate with this service per
time unit.
<b><a href="postconf.5.html#smtpd_per_record_deadline">smtpd_per_record_deadline</a> (normal: no, overload: yes)</b>
Change the behavior of the <a href="postconf.5.html#smtpd_timeout">smtpd_timeout</a> and <a href="postconf.5.html#smtpd_starttls_timeout">smtpd_start</a>-
- <a href="postconf.5.html#smtpd_starttls_timeout">tls_timeout</a> time limits, from a time limit per read or write
- system call, to a time limit to send or receive a complete
- record (an SMTP command line, SMTP response line, SMTP message
+ <a href="postconf.5.html#smtpd_starttls_timeout">tls_timeout</a> time limits, from a time limit per read or write
+ system call, to a time limit to send or receive a complete
+ record (an SMTP command line, SMTP response line, SMTP message
content line, or TLS protocol message).
<b>TARPIT CONTROLS</b>
- When a remote SMTP client makes errors, the Postfix SMTP server can
- insert delays before responding. This can help to slow down run-away
- software. The behavior is controlled by an error counter that counts
+ When a remote SMTP client makes errors, the Postfix SMTP server can
+ insert delays before responding. This can help to slow down run-away
+ software. The behavior is controlled by an error counter that counts
the number of errors within an SMTP session that a client makes without
delivering mail.
<b><a href="postconf.5.html#smtpd_error_sleep_time">smtpd_error_sleep_time</a> (1s)</b>
- With Postfix version 2.1 and later: the SMTP server response
- delay
after a client has made more than $<a href="postconf.5.html#smtpd_soft_error_limit">smtpd_soft_error_limit</a>
- errors, and fewer than $<a href="postconf.5.html#smtpd_hard_error_limit">smtpd_hard_error_limit</a> errors, without
+ With Postfix version 2.1 and later: the SMTP server response
+ delay
after a client has made more than $<a href="postconf.5.html#smtpd_soft_error_limit">smtpd_soft_error_limit</a>
+ errors, and fewer than $<a href="postconf.5.html#smtpd_hard_error_limit">smtpd_hard_error_limit</a> errors, without
delivering mail.
<b><a href="postconf.5.html#smtpd_soft_error_limit">smtpd_soft_error_limit</a> (10)</b>
- The number of errors a remote SMTP client is allowed to make
- without delivering mail before the Postfix SMTP server slows
+ The number of errors a remote SMTP client is allowed to make
+ without delivering mail before the Postfix SMTP server slows
down all its responses.
<b><a href="postconf.5.html#smtpd_hard_error_limit">smtpd_hard_error_limit</a> (normal: 20, overload: 1)</b>
- The maximal number of errors a remote SMTP client is allowed to
+ The maximal number of errors a remote SMTP client is allowed to
make without delivering mail.
<b><a href="postconf.5.html#smtpd_junk_command_limit">smtpd_junk_command_limit</a> (normal: 100, overload: 1)</b>
- The number of junk commands (NOOP, VRFY, ETRN or RSET) that a
- remote SMTP client can send before the Postfix SMTP server
+ The number of junk commands (NOOP, VRFY, ETRN or RSET) that a
+ remote SMTP client can send before the Postfix SMTP server
starts to increment the error counter with each junk command.
Available in Postfix version 2.1 and later:
<b><a href="postconf.5.html#smtpd_recipient_overshoot_limit">smtpd_recipient_overshoot_limit</a> (1000)</b>
- The number of recipients that a remote SMTP client can send in
+ The number of recipients that a remote SMTP client can send in
excess of the limit specified with $<a href="postconf.5.html#smtpd_recipient_limit">smtpd_recipient_limit</a>,
- before the Postfix SMTP server increments the per-session error
+ before the Postfix SMTP server increments the per-session error
count for each excess recipient.
<b>ACCESS POLICY DELEGATION CONTROLS</b>
- As of version 2.1, Postfix can be configured to delegate access policy
- decisions to an external server that runs outside Postfix. See the
+ As of version 2.1, Postfix can be configured to delegate access policy
+ decisions to an external server that runs outside Postfix. See the
file <a href="SMTPD_POLICY_README.html">SMTPD_POLICY_README</a> for more information.
<b><a href="postconf.5.html#smtpd_policy_service_max_idle">smtpd_policy_service_max_idle</a> (300s)</b>
- The time after which an idle SMTPD policy service connection is
+ The time after which an idle SMTPD policy service connection is
closed.
<b><a href="postconf.5.html#smtpd_policy_service_max_ttl">smtpd_policy_service_max_ttl</a> (1000s)</b>
- The time after which an active SMTPD policy service connection
+ The time after which an active SMTPD policy service connection
is closed.
<b><a href="postconf.5.html#smtpd_policy_service_timeout">smtpd_policy_service_timeout</a> (100s)</b>
delegated SMTPD policy server.
<b>ACCESS CONTROLS</b>
- The <a href="SMTPD_ACCESS_README.html">SMTPD_ACCESS_README</a> document gives an introduction to all the SMTP
+ The <a href="SMTPD_ACCESS_README.html">SMTPD_ACCESS_README</a> document gives an introduction to all the SMTP
server access control features.
<b><a href="postconf.5.html#smtpd_delay_reject">smtpd_delay_reject</a> (yes)</b>
- Wait until the RCPT TO command before evaluating
+ Wait until the RCPT TO command before evaluating
$<a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a>, $<a href="postconf.5.html#smtpd_helo_restrictions">smtpd_helo_restrictions</a> and
$<a href="postconf.5.html#smtpd_sender_restrictions">smtpd_sender_restrictions</a>, or wait until the ETRN command
- before evaluating $<a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a> and
+ before evaluating $<a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a> and
$<a href="postconf.5.html#smtpd_helo_restrictions">smtpd_helo_restrictions</a>.
<b><a href="postconf.5.html#parent_domain_matches_subdomains">parent_domain_matches_subdomains</a> (see 'postconf -d' output)</b>
cally, instead of requiring an explicit ".domain.tld" pattern.
<b><a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a> (empty)</b>
- Optional restrictions that the Postfix SMTP server applies in
+ Optional restrictions that the Postfix SMTP server applies in
the context of a client connection request.
<b><a href="postconf.5.html#smtpd_helo_required">smtpd_helo_required</a> (no)</b>
- Require that a remote SMTP client introduces itself with the
- HELO or EHLO command before sending the MAIL command or other
+ Require that a remote SMTP client introduces itself with the
+ HELO or EHLO command before sending the MAIL command or other
commands that require EHLO negotiation.
<b><a href="postconf.5.html#smtpd_helo_restrictions">smtpd_helo_restrictions</a> (empty)</b>
- Optional restrictions that the Postfix SMTP server applies in
+ Optional restrictions that the Postfix SMTP server applies in
the context of a client HELO command.
<b><a href="postconf.5.html#smtpd_sender_restrictions">smtpd_sender_restrictions</a> (empty)</b>
- Optional restrictions that the Postfix SMTP server applies in
+ Optional restrictions that the Postfix SMTP server applies in
the context of a client MAIL FROM command.
<b><a href="postconf.5.html#smtpd_recipient_restrictions">smtpd_recipient_restrictions</a> (see 'postconf -d' output)</b>
- Optional restrictions that the Postfix SMTP server applies in
- the context of a client RCPT TO command, after
+ Optional restrictions that the Postfix SMTP server applies in
+ the context of a client RCPT TO command, after
<a href="postconf.5.html#smtpd_relay_restrictions">smtpd_relay_restrictions</a>.
<b><a href="postconf.5.html#smtpd_etrn_restrictions">smtpd_etrn_restrictions</a> (empty)</b>
- Optional restrictions that the Postfix SMTP server applies in
+ Optional restrictions that the Postfix SMTP server applies in
the context of a client ETRN command.
<b><a href="postconf.5.html#allow_untrusted_routing">allow_untrusted_routing</a> (no)</b>
- Forward mail with sender-specified routing
- (user[@%!]remote[@%!]site) from untrusted clients to destina-
+ Forward mail with sender-specified routing
+ (user[@%!]remote[@%!]site) from untrusted clients to destina-
tions matching $<a href="postconf.5.html#relay_domains">relay_domains</a>.
<b><a href="postconf.5.html#smtpd_restriction_classes">smtpd_restriction_classes</a> (empty)</b>
User-defined aliases for groups of access restrictions.
<b><a href="postconf.5.html#smtpd_null_access_lookup_key">smtpd_null_access_lookup_key</a> (</b><><b>)</b>
- The lookup key to be used in SMTP <a href="access.5.html"><b>access</b>(5)</a> tables instead of
+ The lookup key to be used in SMTP <a href="access.5.html"><b>access</b>(5)</a> tables instead of
the null sender address.
<b><a href="postconf.5.html#permit_mx_backup_networks">permit_mx_backup_networks</a> (empty)</b>
- Restrict the use of the <a href="postconf.5.html#permit_mx_backup">permit_mx_backup</a> SMTP access feature to
+ Restrict the use of the <a href="postconf.5.html#permit_mx_backup">permit_mx_backup</a> SMTP access feature to
only domains whose primary MX hosts match the listed networks.
Available in Postfix version 2.0 and later:
applies in the context of the SMTP DATA command.
<b><a href="postconf.5.html#smtpd_expansion_filter">smtpd_expansion_filter</a> (see 'postconf -d' output)</b>
- What characters are allowed in $name expansions of RBL reply
+ What characters are allowed in $name expansions of RBL reply
templates.
Available in Postfix version 2.1 and later:
<b><a href="postconf.5.html#smtpd_reject_unlisted_sender">smtpd_reject_unlisted_sender</a> (no)</b>
- Request that the Postfix SMTP server rejects mail from unknown
- sender
addresses, even when no explicit <a href="postconf.5.html#reject_unlisted_sender">reject_unlisted_sender</a>
+ Request that the Postfix SMTP server rejects mail from unknown
+ sender
addresses, even when no explicit <a href="postconf.5.html#reject_unlisted_sender">reject_unlisted_sender</a>
access restriction is specified.
<b><a href="postconf.5.html#smtpd_reject_unlisted_recipient">smtpd_reject_unlisted_recipient</a> (yes)</b>
- Request that the Postfix SMTP server rejects mail for unknown
- recipient addresses, even when no explicit
+ Request that the Postfix SMTP server rejects mail for unknown
+ recipient addresses, even when no explicit
<a href="postconf.5.html#reject_unlisted_recipient">reject_unlisted_recipient</a> access restriction is specified.
Available in Postfix version 2.2 and later:
<b><a href="postconf.5.html#smtpd_relay_restrictions">smtpd_relay_restrictions</a> (<a href="postconf.5.html#permit_mynetworks">permit_mynetworks</a>, <a href="postconf.5.html#permit_sasl_authenticated">permit_sasl_authenticated</a>,</b>
<b><a href="postconf.5.html#defer_unauth_destination">defer_unauth_destination</a>)</b>
Access restrictions for mail relay control that the Postfix SMTP
- server applies in the context of the RCPT TO command, before
+ server applies in the context of the RCPT TO command, before
<a href="postconf.5.html#smtpd_recipient_restrictions">smtpd_recipient_restrictions</a>.
<b>SENDER AND RECIPIENT ADDRESS VERIFICATION CONTROLS</b>
- Postfix version 2.1 introduces sender and recipient address verifica-
+ Postfix version 2.1 introduces sender and recipient address verifica-
tion. This feature is implemented by sending probe email messages that
are not actually delivered. This feature is requested via the
- <a href="postconf.5.html#reject_unverified_sender">reject_unverified_sender</a> and <a href="postconf.5.html#reject_unverified_recipient">reject_unverified_recipient</a> access
- restrictions. The status of verification probes is maintained by the
- <a href="verify.8.html"><b>verify</b>(8)</a> server. See the file <a href="ADDRESS_VERIFICATION_README.html">ADDRESS_VERIFICATION_README</a> for infor-
- mation about how to configure and operate the Postfix sender/recipient
+ <a href="postconf.5.html#reject_unverified_sender">reject_unverified_sender</a> and <a href="postconf.5.html#reject_unverified_recipient">reject_unverified_recipient</a> access
+ restrictions. The status of verification probes is maintained by the
+ <a href="verify.8.html"><b>verify</b>(8)</a> server. See the file <a href="ADDRESS_VERIFICATION_README.html">ADDRESS_VERIFICATION_README</a> for infor-
+ mation about how to configure and operate the Postfix sender/recipient
address verification service.
<b><a href="postconf.5.html#address_verify_poll_count">address_verify_poll_count</a> (normal: 3, overload: 1)</b>
fication request in progress.
<b><a href="postconf.5.html#address_verify_sender">address_verify_sender</a> ($<a href="postconf.5.html#double_bounce_sender">double_bounce_sender</a>)</b>
- The sender address to use in address verification probes; prior
+ The sender address to use in address verification probes; prior
to Postfix 2.5 the default was "postmaster".
<b><a href="postconf.5.html#unverified_sender_reject_code">unverified_sender_reject_code</a> (450)</b>
address is rejected by the <a href="postconf.5.html#reject_unverified_sender">reject_unverified_sender</a> restriction.
<b><a href="postconf.5.html#unverified_recipient_reject_code">unverified_recipient_reject_code</a> (450)</b>
- The numerical Postfix SMTP server response when a recipient
- address is rejected by the <a href="postconf.5.html#reject_unverified_recipient">reject_unverified_recipient</a> restric-
+ The numerical Postfix SMTP server response when a recipient
+ address is rejected by the <a href="postconf.5.html#reject_unverified_recipient">reject_unverified_recipient</a> restric-
tion.
Available in Postfix version 2.6 and later:
<b><a href="postconf.5.html#unverified_sender_defer_code">unverified_sender_defer_code</a> (450)</b>
- The numerical Postfix SMTP server response code when a sender
+ The numerical Postfix SMTP server response code when a sender
address probe fails due to a temporary error condition.
<b><a href="postconf.5.html#unverified_recipient_defer_code">unverified_recipient_defer_code</a> (450)</b>
- The numerical Postfix SMTP server response when a recipient
+ The numerical Postfix SMTP server response when a recipient
address probe fails due to a temporary error condition.
<b><a href="postconf.5.html#unverified_sender_reject_reason">unverified_sender_reject_reason</a> (empty)</b>
<a href="postconf.5.html#reject_unverified_recipient">reject_unverified_recipient</a>.
<b><a href="postconf.5.html#unverified_sender_tempfail_action">unverified_sender_tempfail_action</a> ($<a href="postconf.5.html#reject_tempfail_action">reject_tempfail_action</a>)</b>
- The
Postfix SMTP server's action when <a href="postconf.5.html#reject_unverified_sender">reject_unverified_sender</a>
+ The
Postfix SMTP server's action when <a href="postconf.5.html#reject_unverified_sender">reject_unverified_sender</a>
fails due to a temporary error condition.
<b><a href="postconf.5.html#unverified_recipient_tempfail_action">unverified_recipient_tempfail_action</a> ($<a href="postconf.5.html#reject_tempfail_action">reject_tempfail_action</a>)</b>
- The
Postfix SMTP server's action when <a href="postconf.5.html#reject_unverified_recipient">reject_unverified_recipi</a>-
+ The
Postfix SMTP server's action when <a href="postconf.5.html#reject_unverified_recipient">reject_unverified_recipi</a>-
<a href="postconf.5.html#reject_unverified_recipient">ent</a> fails due to a temporary error condition.
Available with Postfix 2.9 and later:
<b><a href="postconf.5.html#address_verify_sender_ttl">address_verify_sender_ttl</a> (0s)</b>
- The time between changes in the time-dependent portion of
+ The time between changes in the time-dependent portion of
address verification probe sender addresses.
<b>ACCESS CONTROL RESPONSES</b>
map "reject" action.
<b><a href="postconf.5.html#defer_code">defer_code</a> (450)</b>
- The numerical Postfix SMTP server response code when a remote
+ The numerical Postfix SMTP server response code when a remote
SMTP client request is rejected by the "defer" restriction.
<b><a href="postconf.5.html#invalid_hostname_reject_code">invalid_hostname_reject_code</a> (501)</b>
- The numerical Postfix SMTP server response code when the client
- HELO or EHLO command parameter is rejected by the
+ The numerical Postfix SMTP server response code when the client
+ HELO or EHLO command parameter is rejected by the
<a href="postconf.5.html#reject_invalid_helo_hostname">reject_invalid_helo_hostname</a> restriction.
<b><a href="postconf.5.html#maps_rbl_reject_code">maps_rbl_reject_code</a> (554)</b>
- The numerical Postfix SMTP server response code when a remote
- SMTP
client request is blocked by the <a href="postconf.5.html#reject_rbl_client">reject_rbl_client</a>,
+ The numerical Postfix SMTP server response code when a remote
+ SMTP
client request is blocked by the <a href="postconf.5.html#reject_rbl_client">reject_rbl_client</a>,
<a href="postconf.5.html#reject_rhsbl_client">reject_rhsbl_client</a>, <a href="postconf.5.html#reject_rhsbl_reverse_client">reject_rhsbl_reverse_client</a>,
<a href="postconf.5.html#reject_rhsbl_sender">reject_rhsbl_sender</a> or <a href="postconf.5.html#reject_rhsbl_recipient">reject_rhsbl_recipient</a> restriction.
<b><a href="postconf.5.html#non_fqdn_reject_code">non_fqdn_reject_code</a> (504)</b>
- The numerical Postfix SMTP server reply code when a client
- request
is rejected by the <a href="postconf.5.html#reject_non_fqdn_helo_hostname">reject_non_fqdn_helo_hostname</a>,
+ The numerical Postfix SMTP server reply code when a client
+ request
is rejected by the <a href="postconf.5.html#reject_non_fqdn_helo_hostname">reject_non_fqdn_helo_hostname</a>,
<a href="postconf.5.html#reject_non_fqdn_sender">reject_non_fqdn_sender</a> or <a href="postconf.5.html#reject_non_fqdn_recipient">reject_non_fqdn_recipient</a> restriction.
<b><a href="postconf.5.html#plaintext_reject_code">plaintext_reject_code</a> (450)</b>
- The numerical Postfix SMTP server response code when a request
+ The numerical Postfix SMTP server response code when a request
is rejected by the <b><a href="postconf.5.html#reject_plaintext_session">reject_plaintext_session</a></b> restriction.
<b><a href="postconf.5.html#reject_code">reject_code</a> (554)</b>
- The numerical Postfix SMTP server response code when a remote
+ The numerical Postfix SMTP server response code when a remote
SMTP client request is rejected by the "reject" restriction.
<b><a href="postconf.5.html#relay_domains_reject_code">relay_domains_reject_code</a> (554)</b>
- The numerical Postfix SMTP server response code when a client
- request is rejected by the <a href="postconf.5.html#reject_unauth_destination">reject_unauth_destination</a> recipient
+ The numerical Postfix SMTP server response code when a client
+ request is rejected by the <a href="postconf.5.html#reject_unauth_destination">reject_unauth_destination</a> recipient
restriction.
<b><a href="postconf.5.html#unknown_address_reject_code">unknown_address_reject_code</a> (450)</b>
The numerical Postfix SMTP server response code when a sender or
- recipient address is rejected by the
- <a href="postconf.5.html#reject_unknown_sender_domain">reject_unknown_sender_domain</a>
or <a href="postconf.5.html#reject_unknown_recipient_domain">reject_unknown_recipient_domain</a>
+ recipient address is rejected by the
+ <a href="postconf.5.html#reject_unknown_sender_domain">reject_unknown_sender_domain</a>
or <a href="postconf.5.html#reject_unknown_recipient_domain">reject_unknown_recipient_domain</a>
restriction.
<b><a href="postconf.5.html#unknown_client_reject_code">unknown_client_reject_code</a> (450)</b>
- The numerical Postfix SMTP server response code when a client
- without valid address <=> name mapping is rejected by the
+ The numerical Postfix SMTP server response code when a client
+ without valid address <=> name mapping is rejected by the
<a href="postconf.5.html#reject_unknown_client_hostname">reject_unknown_client_hostname</a> restriction.
<b><a href="postconf.5.html#unknown_hostname_reject_code">unknown_hostname_reject_code</a> (450)</b>
- The numerical Postfix SMTP server response code when the host-
- name specified with the HELO or EHLO command is rejected by the
+ The numerical Postfix SMTP server response code when the host-
+ name specified with the HELO or EHLO command is rejected by the
<a href="postconf.5.html#reject_unknown_helo_hostname">reject_unknown_helo_hostname</a> restriction.
Available in Postfix version 2.0 and later:
<b><a href="postconf.5.html#default_rbl_reply">default_rbl_reply</a> (see 'postconf -d' output)</b>
- The default Postfix SMTP server response template for a request
+ The default Postfix SMTP server response template for a request
that is rejected by an RBL-based restriction.
<b><a href="postconf.5.html#multi_recipient_bounce_reject_code">multi_recipient_bounce_reject_code</a> (550)</b>
- The numerical Postfix SMTP server response code when a remote
- SMTP
client request is blocked by the <a href="postconf.5.html#reject_multi_recipient_bounce">reject_multi_recipi</a>-
+ The numerical Postfix SMTP server response code when a remote
+ SMTP
client request is blocked by the <a href="postconf.5.html#reject_multi_recipient_bounce">reject_multi_recipi</a>-
<a href="postconf.5.html#reject_multi_recipient_bounce">ent_bounce</a> restriction.
<b><a href="postconf.5.html#rbl_reply_maps">rbl_reply_maps</a> (empty)</b>
<b><a href="postconf.5.html#access_map_defer_code">access_map_defer_code</a> (450)</b>
The numerical Postfix SMTP server response code for an <a href="access.5.html"><b>access</b>(5)</a>
- map "defer" action, including "<a href="postconf.5.html#defer_if_permit">defer_if_permit</a>" or
+ map "defer" action, including "<a href="postconf.5.html#defer_if_permit">defer_if_permit</a>" or
"<a href="postconf.5.html#defer_if_reject">defer_if_reject</a>".
<b><a href="postconf.5.html#reject_tempfail_action">reject_tempfail_action</a> (<a href="postconf.5.html#defer_if_permit">defer_if_permit</a>)</b>
- The Postfix SMTP server's action when a reject-type restriction
+ The Postfix SMTP server's action when a reject-type restriction
fails due to a temporary error condition.
<b><a href="postconf.5.html#unknown_helo_hostname_tempfail_action">unknown_helo_hostname_tempfail_action</a> ($<a href="postconf.5.html#reject_tempfail_action">reject_tempfail_action</a>)</b>
- The
Postfix SMTP server's action when <a href="postconf.5.html#reject_unknown_helo_hostname">reject_unknown_helo_host</a>-
+ The
Postfix SMTP server's action when <a href="postconf.5.html#reject_unknown_helo_hostname">reject_unknown_helo_host</a>-
<a href="postconf.5.html#reject_unknown_helo_hostname">name</a> fails due to an temporary error condition.
<b><a href="postconf.5.html#unknown_address_tempfail_action">unknown_address_tempfail_action</a> ($<a href="postconf.5.html#reject_tempfail_action">reject_tempfail_action</a>)</b>
- The Postfix SMTP server's action when
- <a href="postconf.5.html#reject_unknown_sender_domain">reject_unknown_sender_domain</a>
or <a href="postconf.5.html#reject_unknown_recipient_domain">reject_unknown_recipient_domain</a>
+ The Postfix SMTP server's action when
+ <a href="postconf.5.html#reject_unknown_sender_domain">reject_unknown_sender_domain</a>
or <a href="postconf.5.html#reject_unknown_recipient_domain">reject_unknown_recipient_domain</a>
fail due to a temporary error condition.
<b>MISCELLANEOUS CONTROLS</b>
<b><a href="postconf.5.html#config_directory">config_directory</a> (see 'postconf -d' output)</b>
- The default location of the Postfix <a href="postconf.5.html">main.cf</a> and <a href="master.5.html">master.cf</a> con-
+ The default location of the Postfix <a href="postconf.5.html">main.cf</a> and <a href="master.5.html">master.cf</a> con-
figuration files.
<b><a href="postconf.5.html#daemon_timeout">daemon_timeout</a> (18000s)</b>
- How much time a Postfix daemon process may take to handle a
+ How much time a Postfix daemon process may take to handle a
request before it is terminated by a built-in watchdog timer.
<b><a href="postconf.5.html#command_directory">command_directory</a> (see 'postconf -d' output)</b>
The location of all postfix administrative commands.
<b><a href="postconf.5.html#double_bounce_sender">double_bounce_sender</a> (double-bounce)</b>
- The sender address of postmaster notifications that are gener-
+ The sender address of postmaster notifications that are gener-
ated by the mail system.
<b><a href="postconf.5.html#ipc_timeout">ipc_timeout</a> (3600s)</b>
- The time limit for sending or receiving information over an
+ The time limit for sending or receiving information over an
internal communication channel.
<b><a href="postconf.5.html#mail_name">mail_name</a> (Postfix)</b>
- The mail system name that is displayed in Received: headers, in
+ The mail system name that is displayed in Received: headers, in
the SMTP greeting banner, and in bounced mail.
<b><a href="postconf.5.html#mail_owner">mail_owner</a> (postfix)</b>
- The UNIX system account that owns the Postfix queue and most
+ The UNIX system account that owns the Postfix queue and most
Postfix daemon processes.
<b><a href="postconf.5.html#max_idle">max_idle</a> (100s)</b>
- The maximum amount of time that an idle Postfix daemon process
+ The maximum amount of time that an idle Postfix daemon process
waits for an incoming connection before terminating voluntarily.
<b><a href="postconf.5.html#max_use">max_use</a> (100)</b>
The internet hostname of this mail system.
<b><a href="postconf.5.html#mynetworks">mynetworks</a> (see 'postconf -d' output)</b>
- The list of "trusted" remote SMTP clients that have more privi-
+ The list of "trusted" remote SMTP clients that have more privi-
leges than "strangers".
<b><a href="postconf.5.html#myorigin">myorigin</a> ($<a href="postconf.5.html#myhostname">myhostname</a>)</b>
- The domain name that locally-posted mail appears to come from,
+ The domain name that locally-posted mail appears to come from,
and that locally posted mail is delivered to.
<b><a href="postconf.5.html#process_id">process_id</a> (read-only)</b>
The location of the Postfix top-level queue directory.
<b><a href="postconf.5.html#recipient_delimiter">recipient_delimiter</a> (empty)</b>
- The set of characters that can separate a user name from its
- extension (example: user+foo), or a .forward file name from its
+ The set of characters that can separate a user name from its
+ extension (example: user+foo), or a .forward file name from its
extension (example: .forward+foo).
<b><a href="postconf.5.html#smtpd_banner">smtpd_banner</a> ($<a href="postconf.5.html#myhostname">myhostname</a> ESMTP $<a href="postconf.5.html#mail_name">mail_name</a>)</b>
- The text that follows the 220 status code in the SMTP greeting
+ The text that follows the 220 status code in the SMTP greeting
banner.
<b><a href="postconf.5.html#syslog_facility">syslog_facility</a> (mail)</b>
The syslog facility of Postfix logging.
<b><a href="postconf.5.html#syslog_name">syslog_name</a> (see 'postconf -d' output)</b>
- The mail system name that is prepended to the process name in
- syslog records, so that "smtpd" becomes, for example, "post-
+ The mail system name that is prepended to the process name in
+ syslog records, so that "smtpd" becomes, for example, "post-
fix/smtpd".
Available in Postfix version 2.2 and later:
<b><a href="postconf.5.html#smtpd_forbidden_commands">smtpd_forbidden_commands</a> (CONNECT, GET, POST)</b>
- List of commands that cause the Postfix SMTP server to immedi-
+ List of commands that cause the Postfix SMTP server to immedi-
ately terminate the session with a 221 code.
Available in Postfix version 2.5 and later:
.fi
.ad
.ft R
+.SH smtpd_sasl_service (default: smtp)
+The service name that is passed to the SASL plug-in that is
+selected with \fBsmtpd_sasl_type\fR and \fBsmtpd_sasl_path\fR.
+.PP
+This feature is available in Postfix 2.11 and later. Prior
+versions behave as if "\fBsmtp\fR" is specified.
.SH smtpd_sasl_tls_security_options (default: $smtpd_sasl_security_options)
The SASL authentication security options that the Postfix SMTP
server uses for TLS encrypted SMTP sessions.
.IP "\fBcyrus_sasl_config_path (empty)\fR"
Search path for Cyrus SASL application configuration files,
currently used only to locate the $smtpd_sasl_path.conf file.
+.PP
+Available in Postfix version 2.11 and later:
+.IP "\fBsmtpd_sasl_service (smtp)\fR"
+The service name that is passed to the SASL plug-in that is
+selected with \fBsmtpd_sasl_type\fR and \fBsmtpd_sasl_path\fR.
.SH "STARTTLS SUPPORT CONTROLS"
.na
.nf
<hr>
+<h2> Warning </h2>
+
+<p> Forward secrecy does not protect against active attacks such
+as forged DNS replies or forged TLS server certificates. If such
+attacks are a concern, then the SMTP client will need to authenticate
+the remote SMTP server in a sufficiently-secure manner. For example,
+by the fingerprint of the public key or certificate. Conventional
+PKI relies on many trusted parties and is easily subverted by a
+state-funded adversary. </p>
+
<h2> Background </h2>
<p> Postfix supports forward secrecy of TLS network communication
individual sessions may be infeasible given a sufficiently-strong
key agreement method. </p>
-<p> Forward secrecy protects network communication in the absence
-of active attacks, i.e. no forged DNS replies, and no forged TLS
-server certificates. If active attacks are a concern, then you will
-need to authenticate the remote SMTP server in a secure manner.
-For example, by the fingerprint of the public key or certificate.
-Conventional PKI relies on too many trusted parties. </p>
-
<p> Topics covered in this document: </p>
<ul>
<li><a href="#client_fs">Forward Secrecy in the Postfix SMTP Client</a>
-<li><a href="#test">How do I know that it works?</a>
+<li><a href="#quick-start">Getting started, quick and dirty</a>
+
+<li><a href="#test">How can I see that a connection has forward secrecy?</a>
+
+<li><a href="#ciphers"> What ciphers provide forward secrecy? </a>
+
+<li><a href="#status"> What do "Anonymous", "Untrusted", etc. in
+Postfix logging mean? </a>
<li><a href="#credits"> Credits </a>
<p> The key-exchange algorithms used for forward secrecy require
the TLS server to designate appropriate "parameters" consisting of a
mathematical "group" and an element of that group called a "generator".
-There are two flavors of "groups" that work with PFS: </p>
+Presently, there are two flavors of "groups" that work with PFS: </p>
<ul>
-<li> Prime field groups. The server needs to be configured with a
-suitably large prime and a corresponding "generator".
+<li> <p> <b> Prime-field groups (EDH):</b> The server needs to be
+configured with a suitably-large prime and a corresponding "generator".
+The acronym for forward secrecy over prime fields is EDH or Ephemeral
+Diffie-Hellman (sometimes also abbreviated as DHE). </p>
-<li> Elliptic curve groups. The server needs to be configured with
-a "named curve". These offer better security at lower computational
-cost than prime field groups, but are not as widely implemented.
+<li> <p> <b> Elliptic-curve groups (EECDH): </b> The server needs
+to be configured with a "named curve". These offer better security
+at lower computational cost than prime field groups, but are not
+as widely implemented. The acronym for the elliptic curve version
+is EECDH which is short for Ephemeral Elliptic Curve Diffie-Hellman.
+</p>
</ul>
-<p> The acronym for forward secrecy over prime fields is EDH or
-Ephemeral Diffie-Hellman (sometimes also abbreviated as DHE). The
-acronym for the elliptic curve version is EECDH which is short for
-Ephemeral Elliptic Curve Diffie-Hellman. </p>
-
<p> It is not essential to know what these are, but one does need
to know that OpenSSL only supports EECDH as of version 1.0.0. Thus
the configuration parameters related to Elliptic Curve forward secrecy
will likely cause interoperability issues with older Exchange servers
and is not recommended for now. </p>
-</ul>
-
<h3> EDH Server support </h3>
<p> Postfix ≥ 2.2 support 1024-bit-prime EDH out of the box,
(it is available only in OpenSSL development snapshots). </p>
<p> At some point Postfix will need to adjust to the new API for
-setting the elliptic curve options. Fortunately, when EECDH support
+setting the elliptic-curve options. Fortunately, when EECDH support
was added to Postfix, it introduced a layer of indirection: </p>
<blockquote>
<h2> <a name="client_fs">Forward Secrecy in the Postfix SMTP Client</a> </h2>
<p> The Postfix ≥ 2.2 SMTP client supports forward secrecy in
-its default configuration. If the remote SMTP server supports
-cipher suites with forward secrecy (and does not override the SMTP
-client cipher preference), then the traffic between the server and
-client will resist decryption even if the server's long-term
-authentication keys are <i>later</i> compromised. </p>
-
-<p> The default Postfix SMTP client cipher lists are correctly ordered
-to prefer EECDH and EDH cipher suites ahead of similar cipher suites
-that don't implement forward secrecy. Administrators are strongly
-discouraged from changing the cipher list definitions. It is likely
-safe to set "smtp_tls_ciphers = medium" if you wish to disable the
-obsolete "export" and "low" grade ciphers even with opportunistic
-TLS. Setting a minimum strength does not change the preference
+its default configuration. No configuration changes are needed
+besides turning on elliptic-curve support with Postfix 2.6 and 2.7
+(see the <a href="#quick-start"> quick-start</a> section). If the
+remote SMTP server supports cipher suites with forward secrecy (and
+does not override the SMTP client's cipher preference), then the
+traffic between the server and client will resist decryption even
+if the server's long-term authentication keys are <i>later</i>
+compromised. </p>
+
+<p> The default Postfix SMTP client cipher lists are correctly
+ordered to prefer EECDH and EDH cipher suites ahead of similar
+cipher suites that don't implement forward secrecy. Administrators
+are strongly discouraged from changing the cipher list definitions.
+It is likely safe to set "smtp_tls_ciphers = medium" if you wish
+to disable the obsolete "export" and "low" grade ciphers even with
+opportunistic TLS. Setting a minimum strength does not change the
+preference
order. Note that strengths higher than "medium" exclude Exchange
2003 and likely other widely used MTAs, thus "high" grade ciphers
should only be used on a case-by-case basis via the <a
<h2><a name="quick-start">Getting started, quick and dirty</a></h2>
-<p> At least one time as root (prime group generation can take a
+<ul>
+
+<li> <p> Postfix 2.6 and 2.7: Enable elliptic-curve support. This
+is the default with Postfix ≥ 2.8.
+
+<blockquote>
+<pre>
+/etc/postfix/main.cf:
+ # Postfix 2.6 or 2.7 only. This is default with Postfix 2.8 and later.
+ smtpd_tls_eecdh_grade = strong
+</pre>
+</blockquote>
+
+<li> <p> Optionally generate non-default EDH parameters for improved
+security against pre-computation attacks and for compatibility with
+Debian-patched EXIM SMTP clients (these require a minimum 2048-bit
+length for the non-export prime). The parameter files are not
+secret, after all these parameters are sent to all SMTP clients in
+the clear. Mode 0644 is fine. </p>
+
+<p> Execute as root (prime group generation can take a
few seconds to a few minutes): </p>
<blockquote>
</pre>
</blockquote>
-<p> Note: greater security against "pre-computation" attacks against
-EDH can be obtained by periodically regenerating the EDH parameters
-as above (an hourly or daily cron job running as root can automate
-this task). The parameter files are not secret, after all these are
-sent to all SMTP clients in the clear. Mode 0644 is fine. </p>
+<p> You can improve security against pre-computation attacks further
+by regenerating the EDH parameters periodically (an hourly or daily
+cron job running as root can automate this task). </p>
<p> Once the parameters are in place, update main.cf as follows: </p>
<blockquote>
<pre>
/etc/postfix/main.cf:
- # Postfix ≥ 2.6
- smtpd_tls_eecdh_grade = strong
- # All versions of Postfix:
smtpd_tls_dh1024_param_file = ${config_directory}/dh2048.pem
smtpd_tls_dh512_param_file = ${config_directory}/dh512.pem
</pre>
</pre>
</blockquote>
-<h2><a name="test">How do I know that it works? </a> </h2>
+</ul>
+
+<h2><a name="test">How can I see that a connection has forward
+secrecy? </a> </h2>
-<p> Postfix reports TLS connection information in several ways: </p>
+<p> Postfix can be configured to report information about the
+negotiated cipher, the corresponding key lengths, and the remote
+peer certificate or public-key verification status. </p>
<ul>
<li> <p> With "smtp_tls_loglevel = 1" and "smtpd_tls_loglevel = 1",
-the Postfix SMTP client and server will log information about, among
-others, the remote peer certificate or public-key verification
-status, the negotiated cipher, and key lengths. The general logfile
-format is: </p>
+the Postfix SMTP client and server will log TLS connection information
+to the maillog file. The general logfile format is: </p>
<blockquote>
<pre>
-postfix/smtp[xxx]: Trusted TLS connection established to host.example.com[192.168.0.2]:25: TLSv1 with cipher XXX (YYY/ZZZ bits)
+postfix/smtp[<i>process-id</i>]: Untrusted TLS connection established
+to host.example.com[192.168.0.2]:25: TLSv1 with cipher <i>cipher-name</i>
+(<i>actual-key-size</i>/<i>raw-key-size</i> bits)
-postfix/smtpd[xxx]: Untrusted TLS connection established from host.example.com[192.168.0.2]: TLSv1 with cipher XXX (YYY/ZZZ bits)
+postfix/smtpd[<i>process-id</i>]: Anonymous TLS connection established
+from host.example.com[192.168.0.2]: TLSv1 with cipher <i>cipher-name</i>
+(<i>actual-key-size</i>/<i>raw-key-size</i> bits)
</pre>
</blockquote>
<li> <p> With "smtpd_tls_received_header = yes", the Postfix SMTP
-server will record similar information in the Received: header in
-the form of comments (text inside parentheses). The general format
-is: </p>
+server will record TLS connection information in the Received:
+header in the form of comments (text inside parentheses). The general
+format depends on the smtpd_tls_ask_ccert setting:
<blockquote>
<pre>
Received: from host.example.com (host.example.com [192.168.0.2])
- (using TLSv1 with cipher XXX (YYY/ZZZ bits))
- (Client CN "host.example.com", Issuer "Wietse Venema" (not verified))
+ (using TLSv1 with cipher <i>cipher-name</i>
+ (<i>actual-key-size</i>/<i>raw-key-size</i> bits))
+ (Client CN "host.example.com", Issuer "John Doe" (not verified))
+
+Received: from host.example.com (host.example.com [192.168.0.2])
+ (using TLSv1 with cipher <i>cipher-name</i>
+ (<i>actual-key-size</i>/<i>raw-key-size</i> bits))
+ (No client certificate requested)
</pre>
</blockquote>
</ul>
-<p> There are dozens of ciphers that support forward secrecy. What
+<p> The next sections will explain what <i>cipher-name</i>,
+<i>key-size</i>, and peer verification status information to expect.
+</p>
+
+<h2><a name="ciphers"> What ciphers provide forward secrecy? </a> </h2>
+
+<p> There are dozens of ciphers that support forward secrecy. What
follows is the beginning of a list of 51 ciphers available with
-OpenSSL 1.0.1e: </p>
+OpenSSL 1.0.1e. The list is sorted in the default Postfix preference
+order. It excludes null ciphers that only authenticate and don't
+encrypt, together with export and low-grade ciphers whose encryption
+is too weak to offer meaningful secrecy. The first column shows the
+cipher name, and the second shows the key exchange method. </p>
<blockquote>
<pre>
</pre>
</blockquote>
+<p> To date, all ciphers that support forward secrecy have one of
+five values for the first component of their OpenSSL name: "AECDH",
+"ECDHE", "ADH", "EDH" or "DHE". Ciphers that don't implement forward
+secrecy have names that don't start with one of these prefixes.
+This pattern is likely to persist until some new key-exchange
+mechanism is invented that also supports forward secrecy. </p>
+
+<p> The actual key length and raw algorithm key length
+are generally the same with non-export ciphers, but may they
+differ for the legacy export ciphers where the actual key
+is artificially shortened. </p>
+
+<h2><a name="status"> What do "Anonymous", "Untrusted", etc. in
+Postfix logging mean? </a> </h2>
+
+<p> The verification levels below are subject to man-in-the-middle
+attacks to different degrees. If such attacks are a concern, then
+the SMTP client will need to authenticate the remote SMTP server
+in a sufficiently-secure manner. For example, by the fingerprint
+of the public key or certificate. Remember that conventional PKI
+relies on many trusted parties and is easily subverted by a
+state-funded adversary. </p>
+
+<dl>
+
+<dt><b>Anonymous</b> (no peer certificate)</dt>
+
+<dd> <p> <b> Postfix SMTP client:</b> With opportunistic TLS (the "may" security level) the Postfix
+SMTP client does not verify any information in the peer certificate.
+In this case it enables and prefers anonymous cipher suites in which
+the remote SMTP server does not present a certificate (these ciphers
+offer forward secrecy of necessity). When the remote SMTP server
+also supports anonymous TLS, and agrees to such a cipher suite, the
+verification status will be logged as "Anonymous". </p> </dd>
+
+<dd> <p> <b> Postfix SMTP server:</b> This is by far most common,
+as client certificates are optional, and the Postfix SMTP server
+does not request client certificates by default (see smtpd_tls_ask_ccert).
+Even when client certificates are requested, the remote SMTP client
+might not send a certificate. Unlike the Postfix SMTP client, the
+Postfix SMTP server "anonymous" verification status does not imply
+that the cipher suite is anonymous, which corresponds to the
+<i>server</i> not sending a certificate. </p> </dd>
+
+<dt><b>Untrusted</b> (peer certificate not signed by trusted CA)</dt>
+
+<dd>
+
+<p> <b> Postfix SMTP client:</b> The remote SMTP server presented
+a certificate, but the Postfix SMTP client was unable to check the
+issuing CA signature. With opportunistic TLS this is common with
+remote SMTP servers that don't support anonymous cipher suites.
+</p>
+
+<p> <b> Postfix SMTP server:</b> The remote SMTP client presented
+a certificate, but the Postfix SMTP server was unable to check the
+issuing CA signature. This can happen when the server is configured
+to request client certificates (see smtpd_tls_ask_ccert). </p>
+
+</dd>
+
+<dt><b>Trusted</b> (peer certificate signed by trusted CA, unverified
+peer name)</dt>
+
+<dd>
+
+<p> <b> Postfix SMTP client:</b> The remote SMTP server's certificate
+was signed by a CA that the Postfix SMTP client trusts, but either
+the client was not configured to verify the destination server name
+against the certificate, or the server certificate did not contain
+any matching names. This is common with opportunistic TLS
+(smtp_tls_security_level is "may" or else "dane" with no usable
+TLSA DNS records) when the Postfix SMTP client's trusted CAs can
+verify the authenticity of the remote SMTP server's certificate,
+but the client is not configured or unable to verify the server
+name. </p>
+
+<p> <b> Postfix SMTP server:</b> The remote SMTP client certificate
+was signed by a CA that the Postfix SMTP server trusts. The Postfix
+SMTP server never verifies the remote SMTP client name against the
+names in the certificate. Since the client chooses to connect to
+the server, the Postfix SMTP server has no expectation of a particular
+client hostname. </p>
+
+</dd>
+
+<dt><b>Verified</b> (peer certificate signed by trusted CA, verified
+peer name)</dt>
+
+<dd>
+
+<p> <b> Postfix SMTP client:</b> The remote SMTP server's certificate
+was signed by a CA that the Postfix SMTP client trusts, and it
+matches one of the expected server names. This implies that the
+Postfix SMTP client enforced verification for the destination server
+name, otherwise the verification status would have been just
+"Trusted". </p>
+
+<p> <b> Postfix SMTP server:</b> The status is never "Verified",
+as the Postfix SMTP server never verifies the remote SMTP client
+name against the names in the certificate. </p>
+
+</dd>
+
+</dl>
+
<h2><a name="credits">Credits </a> </h2>
<ul>
<h4><a name="server_dovecot_comm">Postfix to Dovecot SASL communication</a></h4>
<p> Communication between the Postfix SMTP server and Dovecot SASL
-happens over a UNIX-domain socket or over a TCP socket. Dovecot 1
-supports UNIX-domain socket communication only. </p>
+happens over a UNIX-domain socket or over a TCP socket. We will
+be using a UNIX-domain socket for better privacy. </p>
-<h5>UNIX-domain socket communication</h5>
-
-<p> The socket
-pathname and the list of mechanisms offered to Postfix need to be
-specified on the Dovecot server side in <code>dovecot.conf</code>.
-</p>
-
-<p> The following example assumes that the Postfix queue is under
-<code>/var/spool/postfix/</code>. </p>
-
-<p> Note: the example uses Dovecot 1 syntax, See http://www.dovecot.org/
-for newer syntax. </p>
+<p> The following fragment for Dovecot version 2 assumes that the
+Postfix queue is under <code>/var/spool/postfix/</code>. </p>
<blockquote>
<pre>
- 1 /etc/dovecot.conf:
- 2 auth default {
- 3 mechanisms = plain login
- 4 passdb pam {
- 5 }
- 6 userdb passwd {
- 7 }
- 8 socket listen {
- 9 client {
-10 path = /var/spool/postfix/private/auth
-11 mode = 0660
-12 user = postfix
-13 group = postfix
-14 }
-15 }
-16 }
+ 1 conf.d/10-master.conf:
+ 2 service auth {
+ 3 ...
+ 4 unix_listener /var/spool/postfix/private/auth {
+ 5 mode = 0660
+ 6 # Assuming the default Postfix user and group
+ 7 user = postfix
+ 8 group = postfix
+ 9 }
+10 ...
+11 }
+12
+13 conf.d/10-auth.conf
+14 auth_mechanisms = plain login
</pre>
</blockquote>
-<p> Line 3 provides <code>plain</code> and <code>login</code> as
-mechanisms for the Postfix SMTP server, line 10 places the Dovecot
-SASL socket in <code>/var/spool/postfix/private/auth</code>, and
-lines 11-13 limit read+write permissions to user and group
-<code>postfix</code> only. </p>
-
-<p> Proceed with the section "<a href="#server_sasl_enable">Enabling
-SASL authentication and authorization in the Postfix SMTP server</a>"
-to turn on and use SASL in the Postfix SMTP server. </p>
-
-<h5>TCP socket communication</h5>
-
-<p> The TCP port and the list of mechanisms offered to Postfix need
-to be specified on the Dovecot server side in <code>10-auth.conf</code>
-and <code>10-master.conf</code>. </p>
-
-<p> The following examples assume that Postfix should communicate
-with Dovecot on TCP port 12345. </p>
-
-<p> Note: the examples use Dovecot 1 syntax, See http://www.dovecot.org/
-for newer syntax. </p>
-
-<blockquote>
-<pre>
-1 /etc/dovecot/conf.d/10-auth.conf:
-2 auth_mechanisms = plain login
-</pre>
-</blockquote>
-
-<p> Line 2 provides plain and login as mechanisms for the Postfix
-SMTP server. </p>
-
-<blockquote>
-<pre>
-1 /etc/dovecot/conf.d/10-master.conf:
-2 service auth {
-3 unix_listener auth-userdb {
-4 }
-5 inet_listener {
-6 port = 12345
-7 }
-8 }
-</pre>
-</blockquote>
-
-<p> Line 5 creates a new TCP socket and line 6 specifies port 12345
-where Dovecot SASL should wait for Postfix authentication requests.
-</p>
+<p> Line 4 places the Dovecot SASL socket in
+<code>/var/spool/postfix/private/auth</code>, lines 5-8 limit
+read+write permissions to user and group <code>postfix</code> only,
+and line 14 provides <code>plain</code> and <code>login</code> as
+mechanisms for the Postfix SMTP server. </p>
<p> Proceed with the section "<a href="#server_sasl_enable">Enabling
SASL authentication and authorization in the Postfix SMTP server</a>"
<p> This feature is available in Postfix 2.3 and later. In earlier
releases it was called <b>smtpd_sasl_application_name</b>. </p>
+%PARAM smtpd_sasl_service smtp
+
+<p> The service name that is passed to the SASL plug-in that is
+selected with <b>smtpd_sasl_type</b> and <b>smtpd_sasl_path</b>.
+</p>
+
+<p> This feature is available in Postfix 2.11 and later. Prior
+versions behave as if "<b>smtp</b>" is specified. </p>
+
%PARAM cyrus_sasl_config_path
<p> Search path for Cyrus SASL application configuration files,
#ifdef HAS_DB
#include <dict_db.h>
#endif
-#ifdef HAS_LMDB
+#if defined(SNAPSHOT) && defined(HAS_LMDB)
#include <dict_lmdb.h>
#endif
#include <inet_proto.h>
#ifdef HAS_DB
dict_db_cache_size = var_db_read_buf;
#endif
-#ifdef HAS_LMDB
+#if defined(SNAPSHOT) && defined(HAS_LMDB)
dict_lmdb_map_size = var_lmdb_map_size;
#endif
inet_windowsize = var_inet_windowsize;
#define DEF_SMTPD_SASL_PATH "smtpd"
extern char *var_smtpd_sasl_path;
+#define VAR_SMTPD_SASL_SERVICE "smtpd_sasl_service"
+#define DEF_SMTPD_SASL_SERVICE "smtp"
+extern char *var_smtpd_sasl_service;
+
#define VAR_CYRUS_CONF_PATH "cyrus_sasl_config_path"
#define DEF_CYRUS_CONF_PATH ""
extern char *var_cyrus_conf_path;
* Patches change both the patchlevel and the release date. Snapshots have no
* patchlevel; they change the release date only.
*/
-#define MAIL_RELEASE_DATE "20131221"
+#define MAIL_RELEASE_DATE "20131228"
#define MAIL_VERSION_NUMBER "2.11"
#ifdef SNAPSHOT
#include <myflock.h>
#include <warn_stat.h>
-#ifdef HAS_LMDB
+#if defined(SNAPSHOT) && defined(HAS_LMDB)
#ifdef PATH_LMDB_H
#include PATH_LMDB_H
#else
DICT_TYPE_HASH, mkmap_hash_open,
DICT_TYPE_BTREE, mkmap_btree_open,
#endif
-#ifdef HAS_LMDB
+#if defined(SNAPSHOT) && defined(HAS_LMDB)
DICT_TYPE_LMDB, mkmap_lmdb_open,
#endif
DICT_TYPE_FAIL, mkmap_fail_open,
/* .IP "\fBcyrus_sasl_config_path (empty)\fR"
/* Search path for Cyrus SASL application configuration files,
/* currently used only to locate the $smtpd_sasl_path.conf file.
+/* .PP
+/* Available in Postfix version 2.11 and later:
+/* .IP "\fBsmtpd_sasl_service (smtp)\fR"
+/* The service name that is passed to the SASL plug-in that is
+/* selected with \fBsmtpd_sasl_type\fR and \fBsmtpd_sasl_path\fR.
/* STARTTLS SUPPORT CONTROLS
/* .ad
/* .fi
bool var_smtpd_sasl_auth_hdr;
char *var_smtpd_sasl_opts;
char *var_smtpd_sasl_path;
+char *var_smtpd_sasl_service;
char *var_cyrus_conf_path;
char *var_smtpd_sasl_realm;
char *var_smtpd_sasl_exceptions_networks;
VAR_LOCAL_RCPT_MAPS, DEF_LOCAL_RCPT_MAPS, &var_local_rcpt_maps, 0, 0,
VAR_SMTPD_SASL_OPTS, DEF_SMTPD_SASL_OPTS, &var_smtpd_sasl_opts, 0, 0,
VAR_SMTPD_SASL_PATH, DEF_SMTPD_SASL_PATH, &var_smtpd_sasl_path, 1, 0,
+ VAR_SMTPD_SASL_SERVICE, DEF_SMTPD_SASL_SERVICE, &var_smtpd_sasl_service, 1, 0,
VAR_CYRUS_CONF_PATH, DEF_CYRUS_CONF_PATH, &var_cyrus_conf_path, 0, 0,
VAR_SMTPD_SASL_REALM, DEF_SMTPD_SASL_REALM, &var_smtpd_sasl_realm, 0, 0,
VAR_SMTPD_SASL_EXCEPTIONS_NETWORKS, DEF_SMTPD_SASL_EXCEPTIONS_NETWORKS, &var_smtpd_sasl_exceptions_networks, 0, 0,
/*
* Set up a new server context for this connection.
*/
-#define SMTPD_SASL_SERVICE "smtp"
#ifdef USE_TLS
tls_flag = state->tls_context != 0;
#else
state->dest_addr : ""),
client_addr = ADDR_OR_EMPTY(state->addr,
CLIENT_ADDR_UNKNOWN),
- service = SMTPD_SASL_SERVICE,
+ service = var_smtpd_sasl_service,
user_realm = REALM_OR_NULL(var_smtpd_sasl_realm),
security_options = sasl_opts_val,
tls_flag = tls_flag)) == 0)
}
req() {
+ local key=$1; shift
local cn=$1; shift
+ key "$key"
openssl req -new -sha256 -key "${key}.pem" 2>/dev/null \
-config <(printf "[req]\n%s\n%s\n[dn]\nCN=%s\n" \
"prompt = no" "distinguished_name = dn" "${cn}")
}
req_nocn() {
+ local key=$1; shift
+
+ key "$key"
openssl req -new -sha256 -subj / -key "${key}.pem" 2>/dev/null \
-config <(printf "[req]\n%s\n[dn]\nCN_default =\n" \
"distinguished_name = dn")
local akid=$1; shift
exts=$(printf "%s\n%s\n%s\n" "$skid" "$akid" "basicConstraints = CA:true")
- key "$key"
- req "$cn" |
+ req "$key" "$cn" |
cert "$cert" "$exts" -signkey "${key}.pem" -set_serial 1 -days 30
}
local cakey=$1; shift
exts=$(printf "%s\n%s\n%s\n" "$skid" "$akid" "basicConstraints = CA:true")
- key "$key"
- req "$cn" |
+ req "$key" "$cn" |
cert "$cert" "$exts" -CA "${ca}.pem" -CAkey "${cakey}.pem" \
-set_serial 2 -days 30 "$@"
}
"basicConstraints = CA:false" \
"extendedKeyUsage = serverAuth" \
"subjectAltName = @alts" "DNS=${cn}")
- key "$key"
- req "$cn" |
+ req "$key" "$cn" |
cert "$cert" "$exts" -CA "${ca}.pem" -CAkey "${cakey}.pem" \
-set_serial 2 -days 30 "$@"
}
"basicConstraints = CA:true" \
"extendedKeyUsage = serverAuth" \
"subjectAltName = @alts" "DNS=${cn}")
- key "$key"
- req "$cn" |
+ req "$key" "$cn" |
cert "$cert" "$exts" -set_serial 1 -days 30 -signkey "${key}.pem" "$@"
}
local key=$1; shift
local cert=$1; shift
- key "$key"
- req_nocn |
+ req_nocn "$key" |
cert "$cert" "" -signkey "${key}.pem" -set_serial 1 -days -1 "$@"
}
unix_recv_fd unix_send_fd stream_recv_fd stream_send_fd hex_code \
myaddrinfo myaddrinfo4 inet_proto sane_basename format_tv \
valid_utf_8 ip_match base32_code msg_rate_delay netstring \
- vstream timecmp
+ vstream timecmp dict_cache
LIB_DIR = ../../lib
INC_DIR = ../../include
$(CC) $(CFLAGS) -DTEST -o $@ $@.c $(LIB) $(SYSLIBS)
mv junk $@.o
+dict_cache: $(LIB)
+ mv $@.o junk
+ $(CC) $(CFLAGS) -DTEST -o $@ $@.c $(LIB) $(SYSLIBS)
+ mv junk $@.o
+
tests: valid_hostname_test mac_expand_test dict_test unescape_test \
hex_quote_test ctable_test inet_addr_list_test base64_code_test \
attr_scan64_test attr_scan0_test dict_pcre_test host_port_test \
*/
return (cp->name);
}
+
+ /*
+ * Test driver with support for interleaved access. First, enter a number of
+ * requests to look up, update or delete a sequence of cache entries, then
+ * interleave those sequences with the "run" command.
+ */
+#ifdef TEST
+#include <msg_vstream.h>
+#include <vstring_vstream.h>
+#include <argv.h>
+#include <stringops.h>
+
+#define DELIMS " "
+#define USAGE "\n\tTo manage settings:" \
+ "\n\tverbose <level> (verbosity level)" \
+ "\n\telapsed <level> (0=don't show elapsed time)" \
+ "\n\tlmdb_map_size <limit> (initial LMDB size limit)" \
+ "\n\tcache <type>:<name> (switch to named database)" \
+ "\n\tstatus (show map size, cache, pending requests)" \
+ "\n\n\tTo manage pending requests:" \
+ "\n\treset (discard pending requests)" \
+ "\n\trun (execute pending requests in interleaved order)" \
+ "\n\n\tTo add a pending request:" \
+ "\n\tquery <key-prefix> <count> (negative to reverse order)" \
+ "\n\tupdate <key-prefix> <count> (negative to reverse order)" \
+ "\n\tdelete <key-prefix> <count> (negative to reverse order)" \
+ "\n\tpurge <key-prefix>" \
+ "\n\tcount <key-prefix>"
+
+ /*
+ * For realism, open the cache with the same flags as postscreen(8) and
+ * verify(8).
+ */
+#define DICT_CACHE_OPEN_FLAGS (DICT_FLAG_DUP_REPLACE | DICT_FLAG_SYNC_UPDATE | \
+ DICT_FLAG_OPEN_LOCK)
+
+ /*
+ * Storage for one request to access a sequence of cache entries.
+ */
+typedef struct DICT_CACHE_SREQ {
+ int flags; /* per-request: reverse, purge */
+ char *cmd; /* command for status report */
+ void (*action) (struct DICT_CACHE_SREQ *, DICT_CACHE *, VSTRING *);
+ char *prefix; /* key prefix */
+ int done; /* progress indicator */
+ int todo; /* number of entries to process */
+ int first_next; /* first/next */
+} DICT_CACHE_SREQ;
+
+#define DICT_CACHE_SREQ_FLAG_PURGE (1<<1) /* purge instead of count */
+#define DICT_CACHE_SREQ_FLAG_REVERSE (1<<2) /* reverse instead of forward */
+
+#define DICT_CACHE_SREQ_LIMIT 10
+
+ /*
+ * All test requests combined.
+ */
+typedef struct DICT_CACHE_TEST {
+ int flags; /* exclusion flags */
+ int size; /* allocated slots */
+ int used; /* used slots */
+ DICT_CACHE_SREQ job_list[1]; /* actually, a bunch */
+} DICT_CACHE_TEST;
+
+#define DICT_CACHE_TEST_FLAG_ITER (1<<0) /* count or purge */
+
+#define STR(x) vstring_str(x)
+
+int show_elapsed = 1; /* show elapsed time */
+
+#if defined(SNAPSHOT) && defined(HAS_LMDB)
+extern size_t dict_lmdb_map_size; /* LMDB-specific */
+
+#endif
+
+/* usage - command-line usage message */
+
+static NORETURN usage(const char *progname)
+{
+ msg_fatal("usage: %s (no argument)", progname);
+}
+
+/* make_tagged_key - make tagged search key */
+
+static void make_tagged_key(VSTRING *bp, DICT_CACHE_SREQ *cp)
+{
+ if (cp->done < 0)
+ msg_panic("make_tagged_key: bad done count: %d", cp->done);
+ if (cp->todo < 1)
+ msg_panic("make_tagged_key: bad todo count: %d", cp->todo);
+ vstring_sprintf(bp, "%s-%d", cp->prefix,
+ (cp->flags & DICT_CACHE_SREQ_FLAG_REVERSE) ?
+ cp->todo - cp->done - 1 : cp->done);
+}
+
+/* create_requests - create request list */
+
+static DICT_CACHE_TEST *create_requests(int count)
+{
+ DICT_CACHE_TEST *tp;
+ DICT_CACHE_SREQ *cp;
+
+ tp = (DICT_CACHE_TEST *) mymalloc(sizeof(DICT_CACHE_TEST) +
+ (count - 1) *sizeof(DICT_CACHE_SREQ));
+ tp->flags = 0;
+ tp->size = count;
+ tp->used = 0;
+ for (cp = tp->job_list; cp < tp->job_list + count; cp++) {
+ cp->flags = 0;
+ cp->cmd = 0;
+ cp->action = 0;
+ cp->prefix = 0;
+ cp->todo = 0;
+ cp->first_next = DICT_SEQ_FUN_FIRST;
+ }
+ return (tp);
+}
+
+/* reset_requests - reset request list */
+
+static void reset_requests(DICT_CACHE_TEST *tp)
+{
+ DICT_CACHE_SREQ *cp;
+
+ tp->flags = 0;
+ tp->used = 0;
+ for (cp = tp->job_list; cp < tp->job_list + tp->size; cp++) {
+ cp->flags = 0;
+ if (cp->cmd) {
+ myfree(cp->cmd);
+ cp->cmd = 0;
+ }
+ cp->action = 0;
+ if (cp->prefix) {
+ myfree(cp->prefix);
+ cp->prefix = 0;
+ }
+ cp->todo = 0;
+ cp->first_next = DICT_SEQ_FUN_FIRST;
+ }
+}
+
+/* free_requests - destroy request list */
+
+static void free_requests(DICT_CACHE_TEST *tp)
+{
+ reset_requests(tp);
+ myfree((char *) tp);
+}
+
+/* run_requests - execute pending requests in interleaved order */
+
+static void run_requests(DICT_CACHE_TEST *tp, DICT_CACHE *dp, VSTRING *bp)
+{
+ DICT_CACHE_SREQ *cp;
+ int todo;
+ struct timeval start;
+ struct timeval finish;
+ struct timeval elapsed;
+
+ if (dp == 0) {
+ msg_warn("no cache");
+ return;
+ }
+ GETTIMEOFDAY(&start);
+ do {
+ todo = 0;
+ for (cp = tp->job_list; cp < tp->job_list + tp->used; cp++) {
+ if (cp->done < cp->todo) {
+ todo = 1;
+ cp->action(cp, dp, bp);
+ }
+ }
+ } while (todo);
+ GETTIMEOFDAY(&finish);
+ timersub(&finish, &start, &elapsed);
+ if (show_elapsed)
+ vstream_printf("Elapsed: %g\n",
+ elapsed.tv_sec + elapsed.tv_usec / 1000000.0);
+
+ reset_requests(tp);
+}
+
+/* show_status - show settings and pending requests */
+
+static void show_status(DICT_CACHE_TEST *tp, DICT_CACHE *dp)
+{
+ DICT_CACHE_SREQ *cp;
+
+#if defined(SNAPSHOT) && defined(HAS_LMDB)
+ vstream_printf("lmdb_map_size\t%ld\n", (long) dict_lmdb_map_size);
+#endif
+ vstream_printf("cache\t%s\n", dp ? dp->name : "(none)");
+
+ vstream_printf("%s\t%s\t%s\t%s\t%s\t%s\n",
+ "cmd", "dir", "prefix", "count", "done", "first/next");
+
+ for (cp = tp->job_list; cp < tp->job_list + tp->used; cp++)
+ if (cp->todo > 0)
+ vstream_printf("%s\t%s\t%s\t%d\t%d\t%d\n",
+ cp->cmd,
+ (cp->flags & DICT_CACHE_SREQ_FLAG_REVERSE) ?
+ "reverse" : "forward",
+ cp->prefix ? cp->prefix : "(null)", cp->todo,
+ cp->done, cp->first_next);
+}
+
+/* query_action - lookup cache entry */
+
+static void query_action(DICT_CACHE_SREQ *cp, DICT_CACHE *dp, VSTRING *bp)
+{
+ const char *lookup;
+
+ make_tagged_key(bp, cp);
+ if ((lookup = dict_cache_lookup(dp, STR(bp))) == 0) {
+ if (dp->error)
+ msg_warn("query_action: query failed: %s: %m", STR(bp));
+ else
+ msg_warn("query_action: query failed: %s", STR(bp));
+ } else if (strcmp(STR(bp), lookup) != 0) {
+ msg_warn("lookup result \"%s\" differs from key \"%s\"",
+ lookup, STR(bp));
+ }
+ cp->done += 1;
+}
+
+/* update_action - update cache entry */
+
+static void update_action(DICT_CACHE_SREQ *cp, DICT_CACHE *dp, VSTRING *bp)
+{
+ make_tagged_key(bp, cp);
+ if (dict_cache_update(dp, STR(bp), STR(bp)) != 0) {
+ if (dp->error)
+ msg_warn("update_action: update failed: %s: %m", STR(bp));
+ else
+ msg_warn("update_action: update failed: %s", STR(bp));
+ }
+ cp->done += 1;
+}
+
+/* delete_action - delete cache entry */
+
+static void delete_action(DICT_CACHE_SREQ *cp, DICT_CACHE *dp, VSTRING *bp)
+{
+ make_tagged_key(bp, cp);
+ if (dict_cache_delete(dp, STR(bp)) != 0) {
+ if (dp->error)
+ msg_warn("delete_action: delete failed: %s: %m", STR(bp));
+ else
+ msg_warn("delete_action: delete failed: %s", STR(bp));
+ }
+ cp->done += 1;
+}
+
+/* iter_action - iterate over cache and act on entries with given prefix */
+
+static void iter_action(DICT_CACHE_SREQ *cp, DICT_CACHE *dp, VSTRING *bp)
+{
+ const char *cache_key;
+ const char *cache_val;
+ const char *what;
+ int len;
+
+ if (dict_cache_sequence(dp, cp->first_next, &cache_key, &cache_val) == 0) {
+ if (strcmp(cache_key, cache_val) != 0)
+ msg_warn("value \"%s\" differs from key \"%s\"",
+ cache_val, cache_key);
+ len = strlen(cp->prefix);
+ if (strncmp(cache_key, cp->prefix, len) == 0 && cache_key[len] == '-') {
+ cp->done += 1;
+ cp->todo = cp->done + 1; /* XXX */
+ if ((cp->flags & DICT_CACHE_SREQ_FLAG_PURGE)
+ && dict_cache_delete(dp, cache_key) != 0) {
+ if (dp->error)
+ msg_warn("purge_action: delete failed: %s: %m", STR(bp));
+ else
+ msg_warn("purge_action: delete failed: %s", STR(bp));
+ }
+ }
+ cp->first_next = DICT_SEQ_FUN_NEXT;
+ } else {
+ what = (cp->flags & DICT_CACHE_SREQ_FLAG_PURGE) ? "purge" : "count";
+ if (dp->error)
+ msg_warn("%s error after %d: %m", what, cp->done);
+ else
+ vstream_printf("prefix=%s %s=%d\n", cp->prefix, what, cp->done);
+ cp->todo = 0;
+ }
+}
+
+ /*
+ * Table-driven support.
+ */
+typedef struct DICT_CACHE_SREQ_INFO {
+ const char *name;
+ int argc;
+ void (*action) (DICT_CACHE_SREQ *, DICT_CACHE *, VSTRING *);
+ int test_flags;
+ int req_flags;
+} DICT_CACHE_SREQ_INFO;
+
+static DICT_CACHE_SREQ_INFO req_info[] = {
+ {"query", 3, query_action},
+ {"update", 3, update_action},
+ {"delete", 3, delete_action},
+ {"count", 2, iter_action, DICT_CACHE_TEST_FLAG_ITER},
+ {"purge", 2, iter_action, DICT_CACHE_TEST_FLAG_ITER, DICT_CACHE_SREQ_FLAG_PURGE},
+ 0,
+};
+
+/* add_request - add a request to the list */
+
+static void add_request(DICT_CACHE_TEST *tp, ARGV *argv)
+{
+ DICT_CACHE_SREQ_INFO *rp;
+ DICT_CACHE_SREQ *cp;
+ int req_flags;
+ int count;
+ char *cmd = argv->argv[0];
+ char *prefix = (argv->argc > 1 ? argv->argv[1] : 0);
+ char *todo = (argv->argc > 2 ? argv->argv[2] : "1"); /* XXX */
+
+ if (tp->used >= tp->size) {
+ msg_warn("%s: request list is full", cmd);
+ return;
+ }
+ for (rp = req_info; /* See below */ ; rp++) {
+ if (rp->name == 0) {
+ vstream_printf("usage: %s\n", USAGE);
+ return;
+ }
+ if (strcmp(rp->name, argv->argv[0]) == 0
+ && rp->argc == argv->argc)
+ break;
+ }
+ req_flags = rp->req_flags;
+ if (todo[0] == '-') {
+ req_flags |= DICT_CACHE_SREQ_FLAG_REVERSE;
+ todo += 1;
+ }
+ if (!alldig(todo) || (count = atoi(todo)) == 0) {
+ msg_warn("%s: bad count: %s", cmd, todo);
+ return;
+ }
+ if (tp->flags & rp->test_flags) {
+ msg_warn("%s: command conflicts with other command", cmd);
+ return;
+ }
+ tp->flags |= rp->test_flags;
+ cp = tp->job_list + tp->used;
+ cp->cmd = mystrdup(cmd);
+ cp->action = rp->action;
+ if (prefix)
+ cp->prefix = mystrdup(prefix);
+ cp->done = 0;
+ cp->flags = req_flags;
+ cp->todo = count;
+ tp->used += 1;
+}
+
+/* main - main program */
+
+int main(int argc, char **argv)
+{
+ DICT_CACHE_TEST *test_job;
+ VSTRING *inbuf = vstring_alloc(100);
+ char *bufp;
+ ARGV *args;
+ DICT_CACHE *cache = 0;
+ int stdin_is_tty;
+
+ msg_vstream_init(argv[0], VSTREAM_ERR);
+ if (argc != 1)
+ usage(argv[0]);
+
+
+ test_job = create_requests(DICT_CACHE_SREQ_LIMIT);
+
+ stdin_is_tty = isatty(0);
+
+ for (;;) {
+ if (stdin_is_tty) {
+ vstream_printf("> ");
+ vstream_fflush(VSTREAM_OUT);
+ }
+ if (vstring_fgets_nonl(inbuf, VSTREAM_IN) == 0)
+ break;
+ bufp = vstring_str(inbuf);
+ if (!stdin_is_tty) {
+ vstream_printf("> %s\n", bufp);
+ vstream_fflush(VSTREAM_OUT);
+ }
+ if (*bufp == '#')
+ continue;
+ args = argv_split(bufp, DELIMS);
+ if (argc == 0) {
+ vstream_printf("usage: %s\n", USAGE);
+ vstream_fflush(VSTREAM_OUT);
+ continue;
+ }
+ if (strcmp(args->argv[0], "verbose") == 0 && args->argc == 2) {
+ msg_verbose = atoi(args->argv[1]);
+ } else if (strcmp(args->argv[0], "elapsed") == 0 && args->argc == 2) {
+ show_elapsed = atoi(args->argv[1]);
+#if defined(SNAPSHOT) && defined(HAS_LMDB)
+ } else if (strcmp(args->argv[0], "lmdb_map_size") == 0 && args->argc == 2) {
+ dict_lmdb_map_size = atol(args->argv[1]);
+#endif
+ } else if (strcmp(args->argv[0], "cache") == 0 && args->argc == 2) {
+ if (cache)
+ dict_cache_close(cache);
+ cache = dict_cache_open(args->argv[1], O_CREAT | O_RDWR,
+ DICT_CACHE_OPEN_FLAGS);
+ } else if (strcmp(args->argv[0], "reset") == 0 && args->argc == 1) {
+ reset_requests(test_job);
+ } else if (strcmp(args->argv[0], "run") == 0 && args->argc == 1) {
+ run_requests(test_job, cache, inbuf);
+ } else if (strcmp(args->argv[0], "status") == 0 && args->argc == 1) {
+ show_status(test_job, cache);
+ } else {
+ add_request(test_job, args);
+ }
+ vstream_fflush(VSTREAM_OUT);
+ argv_free(args);
+ }
+
+ vstring_free(inbuf);
+ free_requests(test_job);
+ if (cache)
+ dict_cache_close(cache);
+ return (0);
+}
+
+#endif
#include <sys_defs.h>
-#ifdef HAS_LMDB
+#if defined(SNAPSHOT) && defined(HAS_LMDB)
/* System library. */
DICT_TYPE_HASH, dict_hash_open,
DICT_TYPE_BTREE, dict_btree_open,
#endif
-#ifdef HAS_LMDB
+#if defined(SNAPSHOT) && defined(HAS_LMDB)
DICT_TYPE_LMDB, dict_lmdb_open,
#endif
#ifdef HAS_NIS
/* Yorktown Heights, NY 10598, USA
/*--*/
-#ifdef HAS_LMDB
+#if defined(SNAPSHOT) && defined(HAS_LMDB)
/* System library. */
projects / thirdparty / postfix.git / commitdiff
