-This is the Postfix 2.11 (experimental) branch.
-
-The stable Postfix release is called postfix-2.10.x where 2=major
-release number, 10=minor release number, x=patchlevel. The stable
+The stable Postfix release is called postfix-2.11.x where 2=major
+release number, 11=minor release number, x=patchlevel. The stable
release never changes except for patches that address bugs or
emergencies. Patches change the patchlevel and the release date.
New features are developed in snapshot releases. These are called
-postfix-2.11-yyyymmdd where yyyymmdd is the release date (yyyy=year,
+postfix-2.12-yyyymmdd where yyyymmdd is the release date (yyyy=year,
mm=month, dd=day). Patches are never issued for snapshot releases;
instead, a new snapshot is released.
If you upgrade from Postfix 2.9 or earlier, read RELEASE_NOTES-2.10
before proceeding.
-Incompatible changes with snapshot 20131217
-===========================================
+Major changes - tls
+-------------------
+
+[Documentation 20131218] The new FORWARD_SECRECY_README document
+conveniently presents all information about Postfix "perfect" forward
+secrecy support in one place: what forward secrecy is, how to tweak
+settings, and what you can expect to see when Postfix uses ciphers
+with forward secrecy.
+
+[Feature 20130602] Support for PKI-less TLS server certificate
+verification, where the CA public key or the server certificate is
+identified via DNSSEC lookup.
+
+This feature introduces a new TLS security level called "dane"
+(DNS-based Authentication of Named Entities) that uses DNSSEC to
+look up CA information for a server TLS certificate. The details
+of DANE core protocols are still evolving, as are the details of
+how DANE should be used in the context of SMTP. Postfix implements
+what appears to be a "rational" subset of the DANE profiles.
-The master_service_disable syntax has changed: use "service/type"
-instead of "service.type". The new form is consistent with master.cf
-parameter namespaces. The old form is still supported to avoid
-breaking existing configurations.
+The problem with PKI is that there are literally hundreds of
+organizations world-wide that can provide a certificate in anyone's
+name. There have been widely-published incidents in recent history
+where a certificate authority gave out an inappropriate certificate
+(e.g., a certificate in the name of Microsoft to someone who did
+not represent Microsoft), where a CA was compromised (e.g., DigiNotar,
+Comodo), or where a CA made operational mistakes (e.g., TURKTRUST).
+Another concern is that a legitimate CA might be coerced to provide
+a certificate that allows its government to play man-in-the-middle
+on TLS traffic and observe the plaintext.
-Major changes with with snapshot 20131217
-=========================================
+Major changes - postscreen whitelisting
+---------------------------------------
-Support for advanced master.cf query and update operations. This
-was implemented primarily to support automated system management
-tools.
+[Feature 20130512] Allow an SMTP client to skip postscreen(8) tests
+based on its postscreen_dnsbl_sites score.
+
+Specify a negative "postscreen_dnsbl_whitelist_threshold" to enable
+this feature. When a client passes the threshold value without
+having failed other tests, all pending or disabled tests are flagged
+as completed.
+
+Major changes - recipient_delimiter
+-----------------------------------
+
+[Feature 20130405] The recipient_delimiter parameter can now specify
+a set of characters. A user name is now separated from its address
+extension by the first character that matches the recipient_delimiter
+set.
+
+For example, specify "recipient_delimiter = +-" to support both the
+Postfix-style "+" and the qmail-style "-" extension delimiter.
+
+As before, this implementation recognizes one delimiter character
+per email address, and one address extension per email address.
+
+Major changes - smtpd access control
+------------------------------------
+
+[Feature 20131031] The check_sasl_access feature can be used to
+block hijacked logins. Like other check_mumble_acces features it
+queries a lookup table (in this case with the SASL login name), and
+it supports the same actions as any Postfix access(5) table.
+
+[Feature 20130924] The reject_known_sender_login_mismatch feature
+applies reject_sender_login_mismatch only to MAIL FROM addresses
+that are known in $smtpd_sender_login_maps.
+
+Major changes - MacOS X
+-----------------------
+
+[Feature 20130325] Full support for kqueue() event handling which
+scales better with large numbers of file handles, plus a workaround
+for timeout handling on file handles (such as /dev/urandom) that
+still do not correctly support poll().
+
+Major changes - master
+----------------------
+
+[Incompat 20131217] The master_service_disable parameter value
+syntax has changed: use "service/type" instead of "service.type".
+The new form is consistent with postconf(1) namespaces for master.cf.
+The old form is still supported to avoid breaking existing
+configurations.
+
+Major changes - milter
+----------------------
+
+[Feature 20131126] Support for ESMTP parameters NOTIFY and ORCPT
+in the SMFIR_ADDRCPT_PAR (add recipient) request. Credits: Andrew
+Ayer.
+
+Major changes - mysql
+---------------------
+
+[Feature 20131117] MySQL client support for option_file, option_group,
+tls_cert_file, tls_key_file, tls_CAfile, tls_CApath, tls_verify_cert.
+Credits: Gareth Palmer.
+
+Major changes - postconf
+------------------------
+
+[Feature 20131217] Support for advanced master.cf query and update
+operations. This was implemented primarily to support automated
+system management tools.
The goal is to make all Postfix master.cf details accessible as
lists of "name=value" pairs, where the names are organized into
that are made with -X or -#.
Again, always execute "postfix reload" after updating master.cf.
-
-Major changes with snapshot 20131031
-====================================
-
-LMDB support is enabled after changes to LMDB lock management. This
-includes creating databases with postmap(1) and postalias(1);
-read/write access by postscreen(8), proxymap(8), verify(8), and
-tlsmgr(8); and database sharing between privileged writer processes
-and unprivileged reader processes without world-writable files.
-
-Major changes with snapshot 20130929
-====================================
-
-Support to create LMDB databases is no longer available for the
-postmap(1) and postalias(1) commands. Instead, consider using cdb:
-to manage root-owned databases under the root-owned config_directory
-(default: /etc/postfix) such as access(5), virtual(5), transport(5).
-
-The reason is that LMDB applications require write access even when
-the application itself is read-only. This violates the principle
-of least privilege, and causes all kinds of problems when a non-root
-process needs to query a root-owned database.
-
-Support to create LMDB databases is available only for unprivileged
-Postfix daemon processes such as postscreen(8), tlsmgr(8) and
-verify(8) that manage postfix-owned databases under the postfix-owned
-data_directory (default: /var/lib/postfix).
-
-Major changes with snapshot 20130927
-====================================
-
-Postfix now handles LMDB "database full" errors automatically. When
-a database becomes full, its size limit is doubled, and other
-processes automatically pick up the new size limit. The lmdb_map_size
-parameter is now mostly irrelevant, and may be removed in the future.
-
-Major changes with snapshot 20130602
-====================================
-
-Support for PKI-less TLS server certificate verification, where the
-CA public key is identified via DNSSEC lookup.
-
-This feature introduces a new TLS security level called "dane"
-(DNS-based Authentication of Named Entities) that uses DNSSEC to
-look up CA information for a server TLS certificate. The details
-of DANE core protocols are still evolving, as are the details of
-how DANE should be used in the context of SMTP. Postfix implements
-what appears to be a "rational" subset of the DANE profiles.
-
-The problem with PKI is that there are literally hundreds of
-organizations world-wide that can provide a certificate in anyone's
-name. There have been widely-published incidents in recent history
-where a certificate authority gave out an inappropriate certificate
-(e.g., a certificate in the name of Microsoft to someone who did
-not represent Microsoft), where a CA was compromised (e.g., DigiNotar,
-Comodo), or where a CA made operational mistakes (e.g., TURKTRUST).
-Another concern is that a legitimate CA might be coerced to provide
-a certificate that allows its government to play man-in-the-middle
-on TLS traffic and observe the plaintext.
-
-Major changes with snapshot 20130512
-====================================
-
-Allow an SMTP client to skip postscreen(8) tests based on its
-postscreen_dnsbl_sites score.
-
-Specify a negative "postscreen_dnsbl_whitelist_threshold" to enable
-this feature. When a client passes the threshold value without
-having failed other tests, all pending or disabled tests are flagged
-as completed.
-
-Major changes with snapshot 20130405
-====================================
-
-The recipient_delimiter parameter can now specify a set of characters.
-A user name is now separated from its address extension by the first
-character that matches the recipient_delimiter set.
-
-For example, specify "recipient_delimiter = +-" to support both the
-Postfix-style "+" and the qmail-style "-" extension delimiter.
-
-As before, this implementation recognizes one delimiter character
-per email address, and one address extension per email address.
-
-Major changes with snapshot 20130319
-====================================
-
-Postfix support for LMDB databases is suspended due to the existence
-of a hard limit (an "out of storage" failure mode that cannot be
-resolved by increasing the database size).
-
-Postfix may support LMDB again when it no longer limits the size
-of Postfix transactions, whether the limit is built into LMDB itself,
-or implicit by requiring an unbounded amount of memory to handle a
-large transaction.
-
-Major changes with snapshot 20130315
-====================================
-
-LMDB support by Howard Chu. This implementation has unexpected
-failure modes that don't exist with other Postfix databases, so
-don't just yet abandon CDB. See LMDB_README for details.
+++ /dev/null
-Wish list:
-
- To un-break "make tests" under src/smtpd, make tests
- 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
- to FORWARD_SECRECY_README.
-
- Move html/index.html source to proto/.
-
- Preserve case in smtpd_resolve_addr() and add a structure
- member for the case-folded address.
-
- Per SASL account rate limits. This requires new infrastructure
- that maintains stats by SASL account.
-
- Watchdog timer to postmap/postalias.
-
- Things to do before the stable release:
-
- Spell-check, double-word check, and HTML validator check.
-
- Discourage the use of "after 220" tests in POSTSCREEN_README
- and the documentation of individual parameter settings.
-
- Remove this file from the stable release.
-
- Things to do after the stable release:
-
- Begin code revision, after DANE support stabilizes. This
- should be one pass that changes only names and no code.
-
- recipient_delimiters = $recipient_delimiter for BC
-
- All source code must specify its original author and
- license statement. Some code modules specify Lutz Jaenicke
- as the original author and fall under his liberal license.
- Code that is added to such a module has the same license
- (or at least something that is not more restrictive). Code
- modules without input from Lutz Jaenicke must state its
- original author and license (preferably no more restrictive
- than Postfix's own license). Currently, too many files list
- Wietse as the original author, and Lutz Jaenicke's license,
- which is wrong.
-
- Code clarity: replace obscure macro/function names: for
- example SMTP_X(XXX) -> VAR_SMTP(XXX), as the purpose is to
- choose between VAR_SMTP_XXX or VAR_LMTP_XXX; replace
- digestpl() etc. with names that make clear what operation
- is being performed (in this case, update a digest with the
- contents of a buffer with the specified length). Replace r
- with res_opt, ditto for other 1-letter names.
-
- We have smtp_host_lookup, smtp_dns_resolver_options, and
- now smtp_dns_support_level. Of these, smtp_dns_resolver_options
- is orthogonal but the rest has overlap.
-
- There needs to be support for automatic migration from the
- deprecated disable_dns_lookups feature to the preferred
- smtp_dns_support_level feature. This support needs to exist
- for several releases before the deprecated feature can be
- removed.
-
- End code revision, after DANE support stabilizes.
-
- It would be nice if the result from one table lookup could
- serve as input for another (e.g. virtual aliases before the
- list of valid recipients). For this to work the magical
- (bare user, domain only, etc.) lookups need to become a
- table property, not a property of the client context.
-
- It would be nice if "bare username" lookup is not hard-coded
- for domains in the local address class.
-
- Don't forget Apple's code donation for fetching mail from
- IMAP server.
-
- Should postconf -o refuse to work without the -x option?
-
- Make 30s caching (feature 20070414) configurable, such that
- 0 means no caching.
-
- Make errno white/blacklist for getpwnam_r etc. and mailbox
- write errors.
-
- smtpd_muble_restrictions rule names are case-insensitive.
- restriction_classes values are case-sensitive but should
- be case-insensitive for consistency with smtpd_muble_restrictions.
-
- Make "rename" the default when postmapping a DB file
- (later: use copy+rename for postmap -i, postmap -d).
-
- Service-name parameters aren't documented in daemon manpages.
-
- When faking up the DSN ORCPT, don't send bare usernames
- from local command-line submission.
-
- lmtp_assume_final is broken. A 2XX response does not imply
- final delivery. The Sieve language implements accept-then-bounce.
-
- postscreen event-driven plug-in interface to send out a
- query in parallel with the Pregreet and DNSBL tests, using
- a simplified version of the policy delegation protocol.
-
- Parallelized queue preprocessing: rip out the queue manager
- code to read queue files and resolve recipients, and run
- it in parallel processes. The queue manager then processes
- their results as they become available. This would eliminate
- the qmgr<->trivial-rewrite bottleneck. This can also eliminate
- much of the scheduling disadvantage of a single queue manager
- compared to hundreds of mail receiving or sending processes
- (especially if there is a way to scan the queue in parallel).
-
- Memory pools for same-type memory objects. This can be
- used to either increase memory locality for frequently-allocated
- objects (MRU allocation) or to make use-after-free bugs
- more detectable (use LRU allocation and wipe the object
- immediately after free(). Finally, same-type memory pools
- prevent object type errors with use-after-free bugs.
-
- "no-cache" option for selected postscreen tests?
-
- Need a new DICT flag to indicate that a map handle supports
- locking. If it doesn't (as with memcache or proxymap
- handles), then postscreen etc. don't need to close a cache
- file after "postfix reload". After a fork() it is OK to
- keep using a memcache or proxymap handle, because the parent
- exits immediately. For this to work, the memcache client
- needs to propagate the flag from a persistent backup map,
- but the proxymap protocol should not propagate this to the
- client.
-
- Different TTL values for different DNSBL sources?
-
- Replace master(8) SIGHUP by very simple socket protocol to
- allow reload of a specific service.
-
- postscreen: in the dummy SMTP engine, log the protocol state
- at time of violation (like smtpd, set state->where initially
- to CONNECT, then update it with the name of the last "known"
- command, or set it to "unimplemented").
-
- The discussion of postscreen cache configuration is in the
- wrong place (how whitelisting works). Move it to the section
- about configuring postscreen.
-
- Before proxymap can be exposed to the network (primarily
- to share postscreen or verify caches), need to enforce
- limits on attribute string name and value length in IPC
- protocols. 10-20KB seems OK. We need to enforce content
- sanity checks (for example, no control characters; Postfix
- does not pass around multi-line data in table lookups). The
- VSTREAM library already supports read/write deadlines. We
- need to use attack-resistant code for numeric conversion.
-
- move flush_init() etc. from defer service clients to the
- bounce daemon? Postfix works best when work can be spread
- out over many clients, instead of over a few servers.
-
- multi_connect() function that takes a list of inet:host:port
- and/or unix:pathname specs, with an explicit "inet" prefix
- argument to handle applications that use host:port only.
- This will simplify multi-host implementation for memcache
- client, dovecot client, and other.
-
- dict_memcache: treat "bad" key as cache miss, i.e. read/write
- the backup database as if the cache did not exist. This
- does not help because most Postfix maps (virtual, canonical,
- access, transport, ...) also don't support spaces in keys.
-
- postscreen: keep the cache open after "postfix reload" when
- it is remote (type memcache: or proxy:). This does not work
- because memcache can use a non-proxied file as backup).
-
- What is the feasibility of adding an mta_name (personality)
- attribute that is propagated via queue files and delivery
- agent requests? It would default to myhostname.
-
- Major performance improvement opportunity (that is until
- everyone runs Postfix queues on SSDs). Investigate the
- viability of a daemon that produces incoming and postdrop
- queue files on request (in reality it would maintain a
- limited queue of "spare" files). Central queue file allocation
- reduces the I/O performance disadvantage that qmgr has when
- 100 smtpd processes are receiving mail, or when lots of
- mail is submitted with the sendmail command line. When an
- smtpd process accepts MAIL FROM, a cleanup daemon requests
- a queue file and receives a queue ID + file handle from the
- queue file daemon. If the queue file daemon is down, the
- cleanup daemon creates the file itself like it does now;
- this can be hidden in the mail_stream library module. If
- the mail transaction is aborted, then the cleanup daemon
- gives the queue file back to the queue file daemon's "spare"
- file pool, saving most of the overhead of creating and
- deleting a queue file (the file would still need to be
- renamed at the start of the next mail transaction). If the
- cleanup daemon is unable to give a file back, then it can
- delete the file like it does now; this can be hidden in the
- mail_stream library module. The whole thing can be
- transparently added to Postfix by adding calls to a
- queue-file-service client to the mail_queue_enter() and
- mail_queue_remove() library routines. Other advantages:
- 1) negligible performance hit when queue file allocation
- happens earlier, so that logging and milters have a queue
- ID for the whole transaction not just the first valid
- recipient; 2) by not removing every queue files we get most
- of the performance gain of a queue based on append/truncate
- instead of the much more expensive create/delete.
-
- Investigate viability of Sendmail dns maps.
-
- Check if FILTER_README has the "postsuper -r" workaround
-
- Bounces without <> in the plaintext section. Apparently,
- some software renders the text as HTML (and therefore
- does not render addresses and other text inside <> ).
-
- Make the rules for how to use close-on-exec more explicit.
-
- Provide separate timeout control for dict_proxy client,
- rewrite client, resolve client, cleanup client, and so on.
- Perhaps a timeout argument to the mail_connect() routines.
-
- Trick from amavisd: save listen socket/fifo/etc state, clear
- their close-on-exec flags, exec the same program file to
- re-initialize (with saved socket state on command line or
- in environment), then restore the listen socket/fifo/etc
- close-on-exec flags. This could be a way to mitigate the
- impact of memory/file leaks, and to implement "postfix
- reload" support for master(8) features that currently don't
- support this.
-
- Sub-second time resolution. The first benefit is to make
- per-destination rate delays more usable. Other applications
- will come up once the support exists. The straightforward
- approach is to represent all time intervals in milliseconds,
- and to update all code that makes system calls with a time
- argument (as well as the compiled-in upper and lower time
- parameter bounds, which are currently in seconds).
- Unfortunately, that limits he maximum time interval to less
- than 25 days on 32-bit systems, and is likely to break
- compatibility (for starters, it cannot even deal with the
- compiled-in 100d upper bound on the queue file lifetime).
- A second option is to have a "compatibility" time base
- switch between milliseconds and seconds; this means extra
- changes to all code that makes system calls with a time
- argument, and the way that the compiled-in upper and lower
- bounds are specified. Some of this can be encapsulated in
- macros like time_to_sec(t), time_to_msec(t) and sec_to_time(t).
- Finally, it is relatively easy to replace the events(3)
- interface to use "double" for the time delay arguments, but
- it is a major pain to convert all main.cf time parameters
- into doubles (converting only some leads to a documentation
- nightmare).
-
- Address verify cache: allow a negative cache "refresh"
- result to purge a "positive" cache entry in some safe manner.
- Currently, the negative cache "refresh" result is discarded,
- address verify cache lookup returns OK, and each lookup
- forces a "refresh" probe until the entry expires.
-
- Some Sendmail configurations trigger sub-optimal behavior
- when the postscreen_whitelist_interfaces parameter lists
- primary MX addresses only. When postscreen's "deep protocol
- tests" are successful on the primary MX address (i.e. they
- result in 4XX responses to RCPT TO), some Sendmail
- configurations keep the primary MX connection open until
- AFTER they finish talking to the backup MX address. The
- problem is that the backup connection runs into a WHITELIST
- VETO condition because the whitelisting database has not
- yet been updated with the PASS NEW result for the primary
- MX connection. Unfortunately postscreen can't update the
- whitelisting database before the primary MX connection is
- closed, because a client may still make a mistake.
-
- Simplify postscreen logic. Individual "fail" flags help to
- avoid repeated testing/logging the same mistake. Individual
- "pass" flags provide evidence that the client didn't skip
- tests by hanging up early. The current global "noforward"
- flag implements the wrong model: instead we need an indicator
- that a client has passed all tests or that all mistakes
- were forgiven.
-
- In the SMTP server, check if the connection is closed before
- replying to ".", and discard the message if the reply can't
- be sent. This reduces the time window for RFC 1047 message
- duplication, and may even prevent the delivery of some spam.
- http://www.exim.org/lurker/message/20070416.103159.9d5ff0ce.en.html
- This requires splitting the SMTP server's commit operation
- into two operations: first, a tentative commit operation
- that performs most of the I/O and processing in milters and
- in the cleanup server; second, a final commit operation
- that is executed only if the remote SMTP client hasn't hung
- up in the mean time. Unfortunately, SMTP-based before-queue
- content filters don't support a tentative commit operation.
-
- Find out how to reproduce Berkeley DB bogus ENOENT errors.
- postscreen does not log this with Berkeley DB 1 (FreeBSD
- 4..8), 4.7.25 (Ubuntu 9.04) and 4.8.24 (Ubuntu 10.04).
-
- postconf command-line option to show the compile-time
- settings (CCARGS, AUXLIBS) in case binary packages
- don't install the makedefs.out file.
-
- events.c: cache the side effects of file descriptor event
- enable/disable operations in user space, and do bulk kernel
- updates at event_loop() time. This can eliminate costly
- system calls with successive event disable/enable operations
- on the same file descriptor. This can also eliminate the
- need for tricky code that tries to avoid the expense of
- successive disable/enable operations. Such code is likely
- to introduce bugs.
-
- When does it pay off to send domains in the active queue
- to a DNS prefetch daemon? Could this generalize to a dynamic
- transport map that piggy-backs domains with the same MX
- host into the same mail delivery transaction?
-
- inline table where the "whitespace replacement" character
- is specified in-line. Ex: inline:XYname1Xvalue1Yname2Xvalue2
- would instantiate a table with (name1, value1) and (name2,
- value2). I'm afraid this is just too ugly.
-
- tlsproxy(8) should receive TLS preferences from postscreen(8)
- and smtpd(8), instead of reading them from main.cf. This
- means that many tlsproxy_ parameters become postscreen_
- parameters, and that tls_server_init() parameters move to
- to tls_server_start(). That is a significant API change.
- It also means tlsproxy can't open all files before chroot().
-
- anvil rate limit for sasl_username.
-
- Encapsulate nbbio buffer access and update by tlsproxy.
-
- Full-duplex support for tlsproxy(8). This requires updating
- events(3) and nbbio(3).
-
- Register automagic destructor for object attached to VSTREAM.
-
- Use different ipc time limits for email message transactions
- (smtpd, pickup)->cleanup and for quick query/reply transactions
- such as address rewriting/resolution. Beware of large time
- limits for local or virtual alias expansion.
-
- permit_tempfail_action (default: defer_if_reject) to be
- used as the default value for dnswl_tempfail_action and
- rhswl_tempfail_action. Steal liberally from the code that
- implements unverified_recipient_tempfail_action etc.
-
- Support filtering of messages that are generated by Postfix:
- This would apply to postmaster notices and bounce messages
- (DKIM), and address verification (BATV).
-
- Consistency: in postconf.proto make <dt>..</dt> tags bold.
-
- postscreen(8): listen on multiple IP addresses and enforce
- that the client contacts the primary MX address first (i.e.
- punish hosts that contact the secondary before the primary).
- The downside with any approach that relies on temporary
- punishment is that it does not scale to configurations
- with multiple equal-preference MX hosts. Such hosts would
- have to share the postscreen cache, causing an unacceptable
- performance bottleneck and a single point of failure.
-
- According to a paper by Ted Unangst at BSDCON09, kqueue
- reports state changes, i.e. kqueue indicates when the socket
- becomes readable. Specifically, he writes when kqueue reports
- a socket becomes readable but no data is read from that
- socket, later kqueue calls won't report the socket as
- readable. That's not what happens on FreeBSD 8.0, where
- kqueue will keep reporting the socket as readable when
- nothing is read. Also, FreeBSD 8.0 kqueue still reports
- the socket as readable after a read operation does not empty
- the kernel buffer. We need a test program for this that
- repeats these tests with OpenBSD and NetBSD (and MacOS X
- once they fix their kqueue implementation).
-
- Would it help if there were different cleanup_service
- parameter names for different message paths? smtpd(8) uses
- the same cleanup_service value for receiving remote mail
- and for submitting postmaster problem reports. Do we need
- separate mumble_cleanup_service_name parameters for "inject",
- "notify" and "forward" (with backwards compatible defaults)?
-
- IF/ENDIF support for CIDR tables.
-
- Need a regular expression table to translate address
- verification responses into hard/soft/accept reply codes.
-
- Is there a way to make sendmail -V work after local alias
- expansion? Majordomo-like mailing lists would benefit from
- this; the example in VERP_README does not work in the general
- case.
-
- When an alias is a member of an :include: list with owner-
- alias, local(8) needs an option to deliver alias or alias->user
- indirectly. What happens when an :include: list with owner-
- alias includes another list?
-
- Don't allow empty result values in pcre and regexp maps.
- Postfix doesn't allow them anywhere else (check this).
-
- Make PCRE_MAX_CAPTURE configurable.
-
- Add some checks for tokens starting with #. A challenge
- is to report sensible context from the guts of some low-level
- parser, without introducing a great deal of clumsiness.
-
- Add sendmail macros for {verify} and maybe other TLS info.
-
- Find out if we are doing the correct thing by looking at
- state->milter_reject_text when expanding {rcpt_addr} or
- {rcpt_host}.
-
- Find out why post_mail() etc. block when the qmgr fifo is
- full (answer: trigger_timeout). How can this cause delays
- in the queue manager? When a recipient bounces during
- (transport, nexthop, address) resolution, it is redirected
- to the error or retry mailer; and bounce-after-delivery is
- asynchrounous so it can't block the queue manager, either.
-
- How to ensure that proxy_read_maps is processed after all
- its dependencies are initialized, or just bite the bullet
- and rewrite the parameter initialization code.
-
- The cleanup virtual alias expansion limit does not really
- deliver on its promises. 1) It promises to truncate the
- result without aborting delivery, which would be undesirable
- anyway, but that is not what it does, so that is good. 2)
- It keeps all the recipients from multi-recipient database
- lookup, then terminates further recursion when the result
- exceeds the expansion limit. This behavior achieves the
- original goal that all things shall have a finite size (even
- though but we don'really care how large they are) but may
- result in surprises when recipients are listed in virtual
- alias domains or need expansion for other reasons. In a
- phone call with Victor, a reasonable way out is to set the
- limit to some large number (100000) and abort delivery when
- the result exceeds the limit.
-
- Should the postscreen save permanent white/black list lookup
- results to the temporary cache, and query the temporary
- cache first? Skipping white/black list lookups will speed
- up the handling of "good" clients without a permanent
- whitelist entry. Of course, this means that updates to the
- white/black lists do not immediately take effect. Workarounds:
- 1) use a shorter temporary cache TTL for clients on the
- permanent black/white lists; 2) ignore cached white/black
- list lookup results after "postfix reload"; 2) adjust the
- logging, for example "WHITELISTED address (cached)" and
- "BLACKLISTED address (cached)" to eliminate surprises.
- Comparing the cache entry time with the white/blacklist
- file modification time is not foolproof: for example, pcre
- or CIDR tables are read only once.
-
- It would be nice if the generic dict_cache(3) cache manager
- could postpone process suicide until cache cleanup is
- completed (but that is not possible when postscreen forks
- into the background to finish already-accepted connections,
- and it is not desirable when a host is being shut down).
-
- When postscreen drops a connection, a 521 "greeting" should
- be of the form "521 servername..." and not have an enhanced
- status code. The "521 5.7.1" form can be used after EHLO.
- Of course no spammer is going to complain about Postfix
- SMTP compliance.
-
- Find a place to document all the mail routing mechanisms
- in one place so people can figure out how Postfix works.
-
- The access map BCC action is marked "not stable", perhaps
- because people would also expect BCC actions in header/body_checks.
- How much would it take to make the queue file editing code
- generally usable?
-
- Move smtpd_command_filter into smtpd_chat_query() and update
- the session transcript (see smtp_chat_reply() for an example).
-
- SMTP connection caching without storing connections, to
- improve TLS mail delivery performance.
-
- Should not milter8_mail_event() unset the "hold" default
- reply? Better, the default reply should not be used for
- this purpose.
-
- Don't send MASTER_STAT_TAKEN/MASTER_STAT_AVAIL when a server
- runs with process limit of 1. But this means the master
- never learns that the process is successful and will always
- pause $service_throttle_time before restarting a failed service.
-
- Don't bother maintaining a per-service lockfile when a
- server runs with process limit of 1. The purpose of the
- lockfile is to avoid thundering herd problems when the kernel
- wakes up multiple processes for each new client connection.
-
- Implement PREPEND action for milter_header_checks. Save the
- to-be-prepended text to buffer, then emit it along with the
- new header.
-
- Fix the header_body_checks API, so that the name of the map
- class (e.g. milter_header_checks) is available for logging.
-
- Fix the mime_state and header_body_checks APIs, so that
- they use VSTRINGs. This simplifies REPLACE actions.
-
- Update FILTER_README for multi-instance support, and rename
- the old document to FILTER_LEGACY_README.
-
- Need to sign delivery status notifications, to avoid surprises
- when eventually people start enforcing DKIM etc. signatures.
-
- Either document or remove the internal_mail_filter_classes
- feature (it's disabled by default).
-
- Make the "unknown recipient" test configurable as
- first|last|never, with "yes"=="last" for backwards
- compatibility. The "first" setting is good for performance
- (stress=yes) when all users are defined in local files; but
- it may perform worse when users are in networked tables.
-
- Cleanup: make DNSBL query format configurable beyond the
- client's reversed IP address.
-
- With 'final delivery' in the LMTP client, need an option
- to also add delivered-to and other pipe(8) features. This
- requires making mail_copy() functionality available in
- non-mailbox context.
-
- Cleanup: modernize the "add missing From: header" code, to
- ``phrase <addr>'' form. Most likely, quote the entire phrase
- if it contains any text that is special, then rfc822_externalize
- the whole thing.
-
- SMTP server: make the server_addr and server_port available
- to policy server, Dovecot, and perhaps Milters.
-
- Med: local and remote source port and IP address for smtpd
- policy hook.
-
- Maybe change maps_rbl_reject_code default to 521, and
- update wording in STRESS_README.
-
- Encapsulate time_t comparisons so that they can be made
- system dependent (use difftime() where available).
-
- Encapsulate time_t conversions (e.g. REC_TYPE_TIME) so that
- they can be made system dependent.
-
- Plan for time_t larger than long, or wait for LP64 to
- dominate the world?
-
- Make "AUTH=<>" appendage to MAIL FROM configurable, enabled
- by default.
-
- To support ternary operator without a huge parsing effort,
- consider ${value?{xxx}:{yyy}} where ${name} is existing
- syntax, and where ?{text} and :{text} are new syntax that
- is unlikely to break existing configurations. Or perhaps
- it's just too ugly.
-
- Write delivery rate delay example (which _README?) and auth
- failure cache example (SASL_README). Then include them in
- SOHO_README.
-
- Look for alternatives for the use of non_smtpd_milters.
- This involves some way to force local submissions to go
- through a local SMTP client and server, without triggering
- "mail loops back to myself" false alarms. The advantage is
- that it makes smtpd_mumble_restrictions available for local
- and remote mail; the disadvantage is that it makes local
- submissions more dependent on networking. One possibility
- is to use "pickup -o content_filter=smtp:127.0.0.1:10025",
- or a dedicated SMTP client/server on UNIX-domain sockets;
- we could also decide to always suppress "mail loop" detection
- for loopback connections. Another option is to have the
- pickup or cleanup server drive an SMTP client directly;
- this would require extension of the mail_stream() interface,
- plus a way to handle bounced/deferred recipients intelligently,
- but it would be at odds with Postfix design where delivery
- agents access queue files directly; exposing delivery agents
- to raw queue files violates another Postfix design principle.
-
- Consolidate duplicated code in *_server_accept_{pass,inet}().
-
- Consolidate duplicated code in {inet,unix,upass}_trigger.c.
-
- In the SMTP client, handle 421 replies in smtp_loop() by
- having the input function raise a flag after detecting 421
- (kill connection caching and be sure to do the right thing
- with RSET probes), leave the smtp_loop() per-command reply
- handlers unchanged, and have the smtp_loop() reader loop
- bail out with smtp_site_fail("server disconnected after
- %s", where), but only in the case that it isn't already in
- the final state. But first we need to clean up the handling
- of do/don't cache, expired, bad and dead sessions.
-
- Combine smtpd_peer.c and qmqpd_peer.c into a single function
- that produces a client context object, and provide attribute
- print/scan routines that pass these client context objects
- around. With this, we no longer have to update multiple
- pieces of code when a client attribute is added. Ditto for
- SASL and TLS context.
-
- Don't log "warning: XXXXX: undeliverable postmaster
- notification discarded" for spam from outside.
-
- Really need a cleanup driver that allows testing against
- Milter applications instead of synthetic events. This would
- have to provide stubs for clients that talk to Postfix
- daemon processes. See if this approach can also be used for
- other daemons.
-
- smtpd(8) exempts $address_verify_sender from access controls,
- but it doesn't know whether cleanup(8) or delivery agents
- modify the sender. Would it be possible to "calibrate" this
- exemption, perhaps by having delivery agents pass the probe
- sender to the verify server, keeping in mind that the probe
- sender may differ per delivery agent due to output rewriting.
-
- Update attr_print/scan() so they can send/receive file
- descriptors. This simplifies kludgy code in many daemons.
-
- Would there be a problem adding $smtpd_mumble_restrictions
- and $smtpd_sender_login_maps to the default proxy_read_maps
- settings?
-
- Remove defer(8) and trace(8) references and man pages. These
- are services not program names. On the other hand we have
- man pages for lmtp(8) and smtp(8), but not for relay(8).
- Likewise, retry(8) does not have a man page.
-
- Bind all deliveries to the same local delivery process,
- making Postfix perform as poorly as monolithic mailers, but
- giving a possibility to eliminate duplicate deliveries.
-
- Maybe declare loop when resolve_local(mxhost) is true?
-
- Update message content length when adding/removing headers.
-
- Need scache size limit.
-
- REDIRECT should override original recipient info, and
- probably override DSN as well.
-
- Update FILTER_README with mailing list suggestions to tag
- with a badness indicator and then filter down-stream.
-
- Make null local-part handling configurable: either expand
- into mailer-daemon (current bahavior) or disallow (strict
- behavior, currently implemented only in the SMTP server).
-
- The type of var_message_limit (and other file size/offset
- configuration parameters or internal protocol attributes)
- should be changed from int to off_t. This also requires
- checking all expressions in which var_message_limit etc.
- appears: qmqpd, netstring, deliver_request, ...
-
- Add M flag (enable multi-recipient delivery) to pipe daemon.
-
- The usage of TLScontext->cache_type is unclear. It specifies
- a TLS session cache type (smtpd, smtp, or lmtp), but it is
- sometimes used as an indicator that TLS session caching is
- unavailable. In reality, that decision is made by not
- registering call-back functions for cache maintenance.
-
- Postfix TLS library code should copy any strings that it
- receives from the application, instead of passing them
- around as pointers. TLScontext->cache_type is a case in
- point.
-
- Are transport:nexthop null fields the same as in the case
- of default_transport etc. parameters?
-
- Don't lose bits when converting st_dev into maildir file
- name. It's 64 bits on Linux. Found with the BEAM source
- code analyzer. Is this really a problem, or are they just
- using 64 bits for upwards compatibility with LP64 systems?
-
- Do or don't introduce unknown_reverse_client_reject_code.
-
- Check that "UINT32 == unsigned int" choice is ok (i.e. LP64
- UNIX).
-
- Tempfail when a Milter application tries to negotiate content
- access, while it is configured in an SMTP server that runs
- before the smtpd_proxy filter.
-
- Log DSN original recipient when rejecting mail.
-
- Keep whitespace between label and ":"?
-
- Make the map case folding/locking options configurable, if
- not at run-time then at least at compile time so we get
- consistent behavior across applications.
-
- Investigate what it would take to eliminate oqmgr, and to
- make the old behavior configurable in a unified queue
- manager. This would shave another 2.7 KLOC from the source
- footprint.
-
- Document the case folding strategy for match_list like
- features.
-
- Eliminate the (incoming,deferred)->active rename operation.
- This requires an in-memory hash of queue file names to avoid
- duplicate open() operations.
-
- Softbounce fallback-to-ISP for SOHO users. This heuristic
- assumes that when direct-to-MX delivery fails with 5XX,
- delivery via the ISP may still succeed. This could be
- implemented by enabling soft bounces for destinations other
- than the smtp_fallback_relay. So the only benefit of this
- over the existing soft_bounce feature is that it has no
- effect on smtp_fallback_relay deliveries.
-
- Centralize main.cf parameter input so that defaults work
- consistently. What about parameter names that are prefixed
- with mail delivery transport names?
-
- Fix default time unit handling so that we can have a default
- bounce lifetime of $maximal_queue_lifetime, without causing
- panics when a non-default maximal_queue_lifetime setting
- includes no time unit.
-
- After the 20051222 ISASCII paranoia, lowercase() lowercases
- ASCII text only.
-
- Privacy: remove local command/pathname details from remote
- delivery status reports, and log them via local msg_warn().
-
- Is it safe to cache a connection after it has been used for
- more than some number of address verification probes?
-
- Try to recognize that Resent- headers appear in blocks,
- newest block first. But don't break on incorrect header
- block organization.
-
- Hard limits on cache sizes (anvil, specifically).
-
- Laptop friendliness: make the qmgr remember when the next
- deferred queue scan needs to be done, and have the pickup
- server stat() the maildrop directory before searching it.
-
- Low: replace_sender/replace_recipient actions in access
- maps, so they can be used in policy servers?
-
- Low: configurable order of local(8) delivery methods.
-
- Med: smtp_connect_timeout_budget (default: 3x smtp_connect_timeout)
- to limit the total time spent trying to connect.
-
- Med: transform IPv4-in-IPv6 address literals to IPv4 form
- when comparing against local IP addresses?
-
- Med: transform IPv4-in-IPv6 address literals to IPv4 form
- when eliminating MX mailer loops?
-
- Med: Postfix requires [] around IPv6 address information
- in match lists such as mynetworks, debug_peer_list etc.,
- but the [] must not be specified in access(5) maps. Other
- places don't care. For now, this gotcha is documented in
- IPV6_README and in postconf(5) with each feature that may
- use IPv6 address information. The general recommendation
- is not to use [] unless absolutely necessary.
-
- Med: the partial address matching of IPv6 addresses in
- access(5) maps is a bit lame: it repeatedly truncates the
- last ":octetpair" from the printable address representation
- until a match is found or until truncation is no longer
- possible. Since one or more ":" are usually omitted from
- the printable IPv6 address representation, this does not
- really try all the possibilities that one might expect to
- be tried. For now, this gotcha is documented in access(5).
-
- Low: reject HELO with any domain name or IP address that
- this MTA is the final destination for.
-
- Low: should the Delivered-To: test in local(8) be configurable?
-
- Low: make mail_addr_find() lookup configurable.
-
- Low: update events.c so that 1-second timer requests do not
- suffer from rounding errors. This is needed for 1-second
- SMTP session caching time limits. A 1-second interval would
- become arbitrarily short when an event is scheduled just
- before the current second rolls over.
-
- Low: configurable internal/system locking method.
-
- Low: add INSTALL section for pre-existing Postfix systems.
-
- Low: add INSTALL section for pre-existing RPM Postfixes.
-
- Low: disallow smtpd_recipient_limit < 100 (the RFC minimum).
-
- Low: noise filter: allow smtp(8) to retry immediately if
- all MXes return a quick ECONNRESET or 4xx reply during the
- initial handshake. Retry once? How many times?
-
- Low: make post-install a "postfix-only script" so it can
- take data from the environment instead of main.cf.
-
- Low: randomize deferred mail backoff.
-
- Med: separate ulimit for delivery to command?
-
- Med: postsuper -r should do something with recipients in
- bounce logfiles, to make sure the sender will be notified.
- To be perfectly safe, no process other than the queue manager
- should move a queue file away from the active queue.
-
- This could involve tagging a queue file, and use up another
- permission bit (postsuper tags a "hot" file, qmgr requeues it).
-
- Low: postsuper re-run after renaming files, but only a
- limited number of times.
-
- Low: smtp-source may block when sending large test messages.
-
- Med: find a way to log the sender address when MAIL FROM
- is rejected due to lack of disk space.
-
- Low: revise other local delivery agent duplicate filters.
-
- Low: all table lookups should consistently use internalized
- (unquoted) or externalized (quoted) forms as lookup keys.
- smtpd, qmgr, local, etc. use unquoted address forms as keys.
- cleanup uses quoted forms.
-
- Low: have a configurable list of errno values for mailbox
- or maildir delivery that result in deferral rather than
- bouncing mail. What about "killed by signal" exits?
-
- Low: after reorganizing configuration parameters, add flags
- to all parameters whose value can be read from file.
-
- Medium: need in-process caching for map lookups. LDAP servers
- seem to need this in particular. Need a way to expire cached
- results that are too old.
-
- Low: generic showq protocol, to allow for more intelligent
- processing than just mailq. Maybe marry this with postsuper.
-
- Low: default domain for appending to unqualified recipients,
- so that unqualified names can be delivered locally.
-
- Low: The $process_id_directory setting is not used anywhere
- in Postfix. Problem reported by Michael Smith, texas.net.
- This should be documented, or better, the code should warn
- about attempts to set read-only parameters.
-
- Low: while converting 8bit text to quoted-printable, perhaps
- use =46rom to avoid having to produce >From when delivering
- to mailbox.
-
- virtual_mailbox_path expression like forward_path, so that
- people can specify prefix and suffix.
projects / thirdparty / postfix.git / commitdiff
