1 ----------------------------
2 strongSwan - Configuration
3 ----------------------------
14 2.4 Four Tunnel case the elegant way with source routing
16 2.6 Roadwarrior case with virtual IP
17 3. Generating X.509 certificates and CRLs with OpenSSL
18 3.1 Generating a CA certificate
19 3.2 Generating a host or user certificate
21 3.4 Revoking a certificate
22 4. Configuring the connections - ipsec.conf
23 4.1 Configuring my side
24 4.2 Multiple certificates
25 4.3 Configuring the peer side using CA certificates
26 4.4 Handling Virtual IPs and wildcard subnets
27 4.5 Protocol and port selectors
28 4.6 IPsec policies based on wildcards
29 4.7 IPsec policies based on CA certificates
30 4.8 Sending certificate requests
31 4.9 IPsec policies based on group attributes
32 5. Configuring certificates and CRLs
33 5.1 Installing CA certificates
34 5.2 Installing optional Certificate Revocation Lists (CRLs)
35 5.3 Dynamic update of certificates and CRLs
36 5.4 Local caching of CRLs
37 5.5 Online Certificate Status Protocol (OCSP)
39 5.7 Configuring the peer side using locally stored certificates
40 6. Configuring the private keys - ipsec.secrets
41 6.1 Loading private key files in PKCS#1 format
42 6.2 Entering passphrases interactively
43 6.3 Multiple private keys
44 7. Configuring CA properties - ipsec.conf
46 8.1 Configuring a smartcard-based connection
47 8.2 Entering the PIN code
48 8.3 PIN-pad equipped smartcard readers
49 8.4 Configuring a smartcard using pkcs15-init
50 8.5 PKCS#1 proxy functions
51 9. Configuring the clients
54 9.3 Safenet/Soft-Remote
57 10. Monitoring functions
58 11. Firewall support functions
59 11.1 Environment variables in the updown script
60 11.2 Automatic insertion and deletion of iptables firewall rules (NEW)
61 11.3 Sample Linux 2.6 _updown_espmark script for iptables < 1.3.5
62 12. Authentication with raw RSA public keys
63 13. Authentication with OpenPGP certificates
64 13.1 OpenPGP certificates
65 13.2 OpenPGP private keys
66 13.3 Monitoring functions
67 13.4 Suppression of certificate request messages
68 14. Additional features
69 14.1 Authentication and encryption algorithms
71 14.3 Dead peer detection
73 15. Copyright statement and acknowledgements
79 strongSwan is an OpenSource IPsec solution for the Linux operating system
80 and currently supports the following features:
82 * runs both on Linux 2.4 (KLIPS) and Linux 2.6 (native IPsec) kernels.
84 * strong 3DES, AES, Serpent, Twofish, or Blowfish encryption.
86 * Authentication based on X.509 certificates or preshared secrets.
88 * IPsec policies based on wildcards or intermediate CAs.
90 * Powerful and flexible IPsec policies based on group attributes.
92 * Retrieval of Certificate Revocation Lists (CRLs) via HTTP or LDAP.
94 * Local caching of fetched CRLs
96 * Full support of the Online Certificate Status Protocol (OCSP, RFC 2560).
98 * CA management functions including OCSP and CRL URIs and default LDAP server.
100 * Optional storage of RSA private keys on smartcards or USB crypto tokens
102 * Standardized PKCS#11 interface with optional proxy functions serving
103 external applications (disc encryption, etc.).
105 * NAT-Traversal (RFC 3947)
107 * Support of Virtual IPs via static configuratin and IKE Mode Config
109 * Support of Delete SA and informational Notification messages.
111 * Dead Peer Detection (DPD, RFC 3706)
113 Compatibility has successfully been tested with peers running the following
116 FreeS/WAN, Openswan, SafeNet/SoftRemote, NCP Secure Entry Client,
117 SonicWALL Global VPN Client, The GreenBow, Microsoft Windows 2000/XP, etc.
119 Furthermore, interoperability with the following VPN gateways
120 has been demonstrated during the IPsec 2001 Conference in Paris:
122 Cisco IOS Routers, Cisco PIX firewall, Cisco VPN3000,
123 Nortel Contivity VPN Switch, NetScreen (FreeS/WAN as responder only),
124 OpenBSD with isakmpd, Netasq, Netcelo, and 6WIND.
126 Potentially any IPsec implementation with X.509 certificate support can
127 be made to cooperate with strongSwan. The latest addition has been the successful
128 interoperability with the Check Point VPN-1 NG gateway.
134 In the following examples we assume for reasons of clarity that left designates
135 the local host and that right is the remote host. Certificates for users, hosts
136 and gateways are issued by a ficticious strongSwan CA. How to generate private keys
137 and certificates using OpenSSL will be explained in section 3. The CA certificate
138 "strongswanCert.pem" must be present on all VPN end points in order to be able to
139 authenticate the peers.
142 2.1 Site-to-site case
145 In this scenario two security gateways moon and sun will connect the
146 two subnets moon-net and sun-net with each other through a VPN tunnel
147 set up between the two gateways:
149 10.1.0.0/16 -- | 192.168.0.1 | === | 192.168.0.2 | -- 10.2.0.0/16
150 moon-net moon sun sun-net
152 Configuration on gateway moon:
154 /etc/ipsec.d/cacerts/strongswanCert.pem
156 /etc/ipsec.d/certs/moonCert.pem
160 : RSA moonKey.pem "<optional passphrase>"
166 leftsubnet=10.1.0.0/16
167 leftcert=moonCert.pem
169 rightsubnet=10.2.0.0/16
170 rightid="C=CH, O=Linux strongSwan, CN=sun.strongswan.org"
173 Configuration on gateway sun:
175 /etc/ipsec.d/cacerts/strongswanCert.pem
177 /etc/ipsec.d/certs/sunCert.pem
181 : RSA sunKey.pem "<optional passphrase>"
187 leftsubnet=10.2.0.0/16
190 rightsubnet=10.1.0.0/16
191 rightid="C=CH, O=Linux strongSwan, CN=moon.strongswan.org"
195 2.2 Host-to-host case
198 This is a setup between two single hosts which don't have a subnet behind
199 them. Although IPsec transport mode would be sufficient for host-to-host
200 connections we will use the default IPsec tunnel mode.
202 | 192.168.0.1 | === | 192.168.0.2 |
205 Configuration on host moon:
207 /etc/ipsec.d/cacerts/strongswanCert.pem
209 /etc/ipsec.d/certs/moonCert.pem
213 : RSA moonKey.pem "<optional passphrase>"
219 leftcert=moonCert.pem
221 rightid="C=CH, O=Linux strongSwan, CN=sun.strongswan.org"
224 Configuration on host sun:
226 /etc/ipsec.d/cacerts/strongswanCert.pem
228 /etc/ipsec.d/certs/sunCert.pem
232 : RSA sunKey.pem "<optional passphrase>"
240 rightid="C=CH, O=Linux strongSwan, CN=moon.strongswan.org"
247 In a site-to-site setup a system administrator logged into the local gateway
248 often would like to access the peer gateway or a server in the subnet behind
249 the peer gateway over a secure IPsec tunnel.Since IP packets leaving a gateway
250 via the outer network interface carry the IP address of this NIC, four IPsec
251 Security Associations (SAs) must be set up to achieve full connectivity. The
252 example below shows how this can be done without much additional typing work ,
253 using the "also" macro which includes connection definitions defined farther
254 down in the ipsec.conf file.
256 10.1.0.0/16 -- | 192.168.0.1 | === | 192.168.0.2 | -- 10.2.0.0/16
257 moon-net moon sun sun-net
259 Configuration on gateway moon:
261 /etc/ipsec.d/cacerts/strongswanCert.pem
263 /etc/ipsec.d/certs/moonCert.pem
267 : RSA moonKey.pem "<optional passphrase>"
272 leftsubnet=10.1.0.0/16
273 rightsubnet=10.2.0.0/16
277 leftsubnet=10.1.0.0/16
281 rightsubnet=10.2.0.0/16
286 leftcert=moonCert.pem
288 rightid="C=CH, O=Linux strongSwan, CN=sun.strongswan.org"
291 Configuration on gateway sun:
293 /etc/ipsec.d/cacerts/strongswanCert.pem
295 /etc/ipsec.d/certs/sunCert.pem
299 : RSA sunKey.pem "<optional passphrase>"
304 leftsubnet=10.2.0.0/16
305 rightsubnet=10.1.0.0/16
309 leftsubnet=10.2.0.0/16
313 rightsubnet=10.1.0.0/16
320 rightid="C=CH, O=Linux strongSwan, CN=moon.strongswan.org"
324 2.4 The four tunnel case the elegant way with source routing
325 --------------------------------------------------------
327 As you certainly agree, the full four tunnel case described in the previous
328 section becomes quite complex. If we could force the source address of the
329 IP packets leaving the gateway through the outer interface to take on the
330 IP address of the inner interface then we could use the single subnet-to-subnet
331 tunnel from section 2.1. Such a setup becomes possible if we use the
332 source routing capabilites of the ip route command that is already used
333 by strongSwan's updown scripts.
335 10.1.0.0/16 -- | 192.168.0.1 | === | 192.168.0.2 | -- 10.2.0.0/16
336 moon-net moon sun sun-net
338 If we assume that the inner IP address of gateway moon is 10.1.0.1
339 and the inner IP address of gateway sun is 10.2.0.1 then the
340 insertion of the parameter
342 leftsourceip=10.1.0.1
344 in the connection definition of moon and
346 leftsourceip=10.2.0.1
348 on sun, respectively, will install source routing on both gateways.
349 As a result the command
353 executed on moon will leave the gateway with a source address of
354 10.1.0.1 and will therefore take the net-net IPsec tunnel.
356 Configuration on gateway moon:
358 /etc/ipsec.d/cacerts/strongswanCert.pem
360 /etc/ipsec.d/certs/moonCert.pem
364 : RSA moonKey.pem "<optional passphrase>"
370 leftsourceip=10.1.0.1
371 leftsubnet=10.1.0.0/16
372 leftcert=moonCert.pem
374 rightsubnet=10.2.0.0/16
375 rightid="C=CH, O=Linux strongSwan, CN=sun.strongswan.org"
378 Configuration on gateway sun:
380 /etc/ipsec.d/cacerts/strongswanCert.pem
382 /etc/ipsec.d/certs/sunCert.pem
386 : RSA sunKey.pem "<optional passphrase>"
392 leftsubnet=10.2.0.0/16
393 leftsourceip=10.2.0.1
396 rightsubnet=10.1.0.0/16
397 rightid="C=CH, O=Linux strongSwan, CN=moon.strongswan.org"
404 This is a very common case where a strongSwan gateway serves an arbitrary number
405 of remote VPN clients usually having dynamic IP addresses.
407 10.1.0.0/16 -- | 192.168.0.1 | === | x.x.x.x |
410 Configuration on gateway moon:
412 /etc/ipsec.d/cacerts/strongswanCert.pem
414 /etc/ipsec.d/certs/moonCert.pem
418 : RSA moonKey.pem "<optional passphrase>"
424 leftsubnet=10.1.0.0/16
425 leftcert=moonCert.pem
429 Configuration on roadwarrior carol:
431 /etc/ipsec.d/cacerts/strongswanCert.pem
433 /etc/ipsec.d/certs/carolCert.pem
437 : RSA carolKey.pem "<optional passphrase>"
443 leftcert=carolCert.pem
445 rightsubnet=10.1.0.0/16
446 rightid="C=CH, O=Linux strongSwan, CN=moon.strongswan.org"
450 2.6 Roadwarrior case with virtual IP
451 --------------------------------
453 Roadwarriors usually have dynamic IP addresses assigned by the ISP they are
454 currently attached to. In order to simplify the routing from moon-net back
455 to the remote access client carol it would be desirable if the roadwarrior had
456 an inner IP address chosen from a pre-assigned pool.
458 10.1.0.0/16 -- | 192.168.0.1 | === | x.x.x.x | -- 10.3.0.1
459 moon-net moon carol virtual IP
461 This virtual IP address can be assigned to a strongSwan roadwarrior by adding
464 leftsourceip=10.3.0.1
466 to the roadwarrior's ipsec.conf. Of course the virtual IP of each roadwarrior
467 must be distinct. In our example it is chosen from the address pool
469 rightsubnetwithin=10.3.0.0/16
471 which can be added to the gateway's ipsec.conf so that a single connection
472 definition can handle multiple roadwarriors.
474 Configuration on gateway moon:
476 /etc/ipsec.d/cacerts/strongswanCert.pem
478 /etc/ipsec.d/certs/moonCert.pem
482 : RSA moonKey.pem "<optional passphrase>"
488 leftsubnet=10.1.0.0/16
489 leftcert=moonCert.pem
491 rightsubnetwithin=10.3.0.0/16
494 Configuration on roadwarrior carol:
496 /etc/ipsec.d/cacerts/strongswanCert.pem
498 /etc/ipsec.d/certs/carolCert.pem
502 : RSA carolKey.pem "<optional passphrase>"
508 leftsourceip=10.3.0.1
509 leftcert=carolCert.pem
511 rightsubnet=10.1.0.0/16
512 rightid="C=CH, O=Linux strongSwan, CN=moon.strongswan.org"
516 3. Generating certificates and CRLs with OpenSSL
517 ---------------------------------------------
519 This section is not a full-blown tutorial on how to use OpenSSL. It just lists
520 a few points that are relevant if you want to generate your own certificates
521 and CRLs for use with strongSwan.
524 3.1 Generating a CA certificate
525 ---------------------------
527 The OpenSSL statement
529 openssl req -x509 -days 1460 -newkey rsa:2048 \
530 -keyout strongswanKey.pem -out strongswanCert.pem
532 creates a 2048 bit RSA private key strongswanKey.pem and a self-signed CA
533 certificate strongswanCert.pem with a validity of 4 years (1460 days).
535 openssl x509 -in cert.pem -noout -text
537 lists the properties of a X.509 certificate cert.pem. It allows you to verify
538 whether the configuration defaults in openssl.cnf have been inserted correctly.
540 If you prefer the CA certificate to be in binary DER format then the following
541 command achieves this transformation:
543 openssl x509 -in strongswanCert.pem -outform DER -out strongswanCert.der
545 The directory /etc/ipsec.d/cacerts contains all required CA certificates either
546 in binary DER or in base64 PEM format. Irrespective of the file suffix, Pluto
547 "automagically" determines the correct format.
550 3.2 Generating a host or user certificate
551 -------------------------------------
553 The OpenSSL statement
555 openssl req -newkey rsa:1024 -keyout hostKey.pem \
558 generates a 1024 bit RSA private key hostKey.pem and a certificate request
559 hostReq.pem which has to be signed by the CA.
561 If you want to add a subjectAltName field to the host certificate you must edit
562 the OpenSSL configuration file openssl.cnf and add the following line in the
563 [ usr_cert ] section:
565 subjectAltName=DNS:moon.strongswan.org
567 if you want to identify the host by its Fully Qualified Domain Name (FQDN ), or
569 subjectAltName=IP:192.168.0.1
571 if you want the ID to be of type IPV4_ADDR. Of course you could include both
574 subjectAltName=DNS:moon.strongswan.org,IP:192.168.0.1
576 but the use of an IP address for the identification of a host should be
579 For user certificates the appropriate ID type is USER_FQDN which can be
582 subjectAltName=email:carol@strongswan.org
584 or if the user's e-mail address is part of the subject's distinguished name
586 subjectAltName=email:copy
588 Now the certificate request can be signed by the CA with the command
590 openssl ca -in hostReq.pem -days 730 -out hostCert.pem -notext
592 If you omit the -days option then the default_days value (365 days) specified
593 in openssl.cnf is used. The -notext option avoids that a human readable
594 listing of the certificate is prepended to the base64 encoded certificate
597 If you want to use the dynamic CRL fetching feature described in section 4.7
598 then you may include one or several crlDistributionPoints in your end
599 certificates. This can be done in the [ usr_cert ] section of the openssl.cnf
602 crlDistributionPoints= @crl_dp
606 URI.1="http://crl.strongswan.org/strongswan.crl"
607 URI.2="ldap://ldap.strongswan.org/cn=strongSwan Root CA, o=Linux strongSwan
608 , c=CH?certificateRevocationList"
610 If you have only a single http distribution point then the short form
612 crlDistributionPoints="URI:http://crl.strongswan.org/strongswan.crl"
614 also works. Due to a known bug in OpenSSL this notation fails with ldap URIs.
616 Usually a Windows-based VPN client needs its private key, its host or
617 user certificate, and the CA certificate. The most convenient way to load
618 this information is to put everything into a PKCS#12 file:
620 openssl pkcs12 -export -inkey carolKey.pem \
621 -in carolCert.pem -name "carol" \
622 -certfile strongswanCert.pem -caname "strongSwan Root CA" \
629 An empty CRL that is signed by the CA can be generated with the command
631 openssl ca -gencrl -crldays 15 -out crl.pem
633 If you omit the -crldays option then the default_crl_days value (30 days)
634 specified in openssl.cnf is used.
636 If you prefer the CRL to be in binary DER format then this conversion
639 openssl crl -in crl.pem -outform DER -out cert.crl
641 The directory /etc/ipsec.d/crls contains all CRLs either in binary DER
642 or in base64 PEM format. Irrespective of the file suffix, Pluto
643 "automagically" determines the correct format.
646 3.4 Revoking a certificate
647 ----------------------
649 A specific host certificate stored in the file host.pem is revoked with the
652 openssl ca -revoke host.pem
654 Next the CRL file must be updated
656 openssl ca -gencrl -crldays 60 -out crl.pem
658 The content of the CRL file can be listed with the command
660 openssl crl -in crl.pem -noout -text
662 in the case of a base64 CRL, or alternatively for a CRL in DER format
664 openssl crl -inform DER -in cert.crl -noout -text
668 4. Configuring the connections - ipsec.conf
669 ----------------------------------------
671 4.1 Configuring my side
674 Usually the local side is the same for all connections. Therefore it makes
675 sense to put the definitions characterizing the strongSwan security gateway into
676 the conn %default section of the configuration file /etc/ipsec.conf. If we
677 assume throughout this document that the strongSwan security gateway is left and
678 the peer is right then we can write
681 # my side is left - the freeswan security gateway
683 leftcert=moonCert.pem
684 # load connection definitions automatically
687 The X.509 certificate by which the strongSwan security gateway will authenticate
688 itself by sending it in binary form to its peers as part of the Internet Key
689 Exchange (IKE) is specified in the line
691 leftcert=moonCert.pem
693 The certificate can either be stored in base64 PEM-format or in the binary
694 DER-format. Irrespective of the file suffix, Pluto "automagically" determines
695 the correct format. Therefore
697 leftcert=moonCert.der
701 leftcert=moonCert.cer
703 would also be valid alternatives.
705 When using relative pathnames as in the examples above, the certificate files
706 must be stored in in the directory /etc/ipsec.d/certs. In order to distinguish
707 strongSwan's own certificates from locally stored trusted peer certificates
708 (see section 5.5 for details), they could also be stored in a subdirectory
709 below /etc/ipsec.d/certs as e.g. in
711 leftcert=mycerts/moonCert.pem
713 Absolute pathnames are also possible as in
715 leftcert=/usr/ssl/certs/moonCert.pem
717 As an ID for the VPN gateway we recommend the use of a Fully Qualified Domain
718 Name (FQDN) of the form
722 leftid=@moon.strongswan.org
724 Important: When an FQDN identifier is used it must be explicitly included as a
725 so called subjectAltName of type dnsName (DNS:) in the certificate indicated
726 by leftcert. For details on how to generate certificates with subjectAltNames,
727 please refer to section 7.2.
729 If you don't want to mess with subjectAltNames, you can use the certificate's
730 Distinguished Name (DN) instead, which is an identifier of type DER_ASN1_DN
731 and which can be written e.g. in the LDAP-type format
735 leftid="C=CH, O=Linux strongSwan, CN=moon.strongswan.org"
737 Since the subject's DN is part of the certificate, the leftid does not have to
738 be declared explicitly. Thus the entry
743 automatically assumes the subject DN of leftcert to be the host ID.
746 4.2 Multiple certificates
747 ---------------------
749 strongSwan supports multiple local host certificates and corresponding
754 rightid=@peer1.domain1
756 # leftid is DN of myCert1
760 rightid=@peer2.domain2
762 # leftid is DN of myCert2
764 When peer1 initiates a connection then strongSwan will send myCert1 and will
765 sign with myKey1 defined in /etc/ipsec.secrets (see section 6.2) whereas
766 myCert2 and myKey2 will be used in a connection setup started from peer2.
769 4.3 Configuring the peer side using CA certificates
770 -----------------------------------------------
772 Now we can proceed to define our connections. In many applications we might
773 have dozens of mostly Windows-based road warriors connecting to a central
774 strongSwan security gateway. The following most simple statement:
779 defines the general roadwarrior case. The line right=%any literally means that
780 any IPSec peer is accepted, regardless of its current IP source address and its
781 ID, as long as the peer presents a valid X.509 certificate signed by a CA the
782 strongSwan security gateway puts explicit trust in. Additionally the signature
783 during IKE main mode gives proof that the peer is in possession of the private
784 RSA key matching the public key contained in the transmitted certificate.
786 The ID by which a peer is identifying itself during IKE main mode can by any of
787 the ID types IPV4_ADDR, FQDN, USER_FQDN or DER_ASN1_DN. If one of the first
788 three ID types is used, then the accompanying X.509 certificate of the peer
789 must contain a matching subjectAltName field of the type ipAddress (IP:),
790 dnsName (DNS:) or rfc822Name (email:), respectively. With the fourth type
791 DER_ASN1_DN the identifier must completely match the subject field of the
792 peer's certificate. One of the two possible representations of a
793 Distinguished Name (DN) is the LDAP-type format
795 rightid="C=CH, O=Linux strongSwan, CN=sun.strongswan.org"
797 Additional whitespace can be added everywhere as desired since it will be
798 automatically eliminated by the X.509 parser. An exception is the single
799 whitespace between individual words , like e.g. in Linux strongSwan, which is
800 preserved by the parser.
802 The Relative Distinguished Names (RDNs) can alternatively be separated by a
803 slash '/' instead of a comma ','
805 rightid="/C=CH/O=Linux strongSwan/CN=sun.strongswan.org"
807 This is the representation extracted from the certificate by the OpenSSL
810 openssl x509 -in sunCert.pem -noout -subject
812 The following RDNs are supported by strongSwan
814 +---------------------------------------------------+
815 | DC Domain Component |
816 |---------------------------------------------------|
818 |---------------------------------------------------|
819 | ST State or province |
820 |---------------------------------------------------|
821 | L Locality or town |
822 |---------------------------------------------------|
824 |---------------------------------------------------|
825 | OU Organisational Unit |
826 |---------------------------------------------------|
828 |---------------------------------------------------|
829 | ND NameDistinguisher, used with CN |
830 |---------------------------------------------------|
832 |---------------------------------------------------|
834 |---------------------------------------------------|
836 |---------------------------------------------------|
838 |---------------------------------------------------|
840 |---------------------------------------------------|
842 |---------------------------------------------------|
844 |---------------------------------------------------|
845 | emailAddress E-mail |
846 |---------------------------------------------------|
848 |---------------------------------------------------|
849 | serialNumber Serial number |
850 |---------------------------------------------------|
852 |---------------------------------------------------|
853 | ID X.500 Unique Identifier |
854 |---------------------------------------------------|
856 |---------------------------------------------------|
857 | TCGID [Siemens] Trust Center Global ID |
858 |---------------------------------------------------|
859 | unstructuredName Unstructured Name |
860 |---------------------------------------------------|
861 | UN Unstructured Name |
862 |---------------------------------------------------|
863 | employeeNumber Employee Number |
864 |---------------------------------------------------|
865 | EN Employee Number |
866 +---------------------------------------------------+
868 With the roadwarrior connection definition listed above, an IPsec SA for
869 the strongSwan security gateway moon.strongswan.org itself can be established.
870 If any roadwarrior should be able to reach e.g. the two subnets 10.1.0.0/24
871 and 10.1.3.0/24 behind the security gateway then the following connection
872 definitions will make this possible
876 leftsubnet=10.1.0.0/24
880 leftsubnet=10.1.3.0/24
882 If not all peers in possession of a X.509 certificate signed by a specific
883 certificate authority shall be given access to the Linux security gateway,
884 then either a subset of them can be barred by listing the serial numbers of
885 their certificates in a certificate revocation list (CRL) as specified in
886 section 5.2 or as an alternative, access can be controlled by explicitly
887 putting a roadwarrior entry for each eligible peer into ipsec.conf:
891 rightid=@sun.strongswan.org
895 rightid=carol@strongswan.org
899 rightid="C=CH, O=Linux strongSwan, CN=dave@strongswan.org"
901 When the IP address of a peer is known to be stable, it can be specified as
902 well. This entry is mandatory when the strongSwan host wants to act as the
903 initiator of an IPSec connection.
907 rightid=@sun.strongswan.org
911 rightid=carol@strongswan.org
915 rightid="C=CH, O=Linux strongSwan, CN=dave@strongswan.org"
920 In the last example the ID types FQDN, USER_FQDN, DER_ASN1_DN and IPV4_ADDR,
921 respectively, were used. Of course all connection definitions presented so far
922 have included the lines in the conn %defaults section, comprising among other
923 a left and leftcert entry.
926 4.4 Handling Virtual IPs and wildcard subnets
927 -----------------------------------------
929 Often roadwarriors are behind NAT-boxes with IPsec passthrough, which causes
930 the inner IP source address of an IPsec tunnel to be different from the
931 outer IP source address usually assigned dynamically by the ISP.
932 Whereas the varying outer IP address can be handled by the right=%any
933 construct, the inner IP address or subnet must always be declared in a
934 connection definition. Therefore for the three roadwarriors rw1 to rw3
935 connecting to a strongSwan security gateway the following entries are
936 required in /etc/ipsec.conf:
940 righsubnet=10.4.0.5/32
944 rightsubnet=10.4.0.47/32
948 rightsubnet=10.4.0.128/28
950 With the wildcard parameter rightsubnetwithin these three entries can be
951 reduced to the single connection definition
955 rightsubnetwithin=10.4.0.0/24
957 Any host will be accepted (of course after successful authentication based on
958 the peer's X.509 certificate only) if it declares a client subnet lying totally
959 within the brackets defined by the wildcard subnet definition (in our example
960 10.4.0.0/24). For each roadwarrior a connection instance tailored to the
961 subnet of the particular client will be created,based on the generic
962 rightsubnetwithin template.
964 This strongSwan feature can also be helpful with VPN clients getting a
965 dynamically assigned inner IP from a DHCP server located on the NAT router box.
968 4.5 Protocol and Port Selectors
969 ---------------------------
971 strongSwan offer the possibility to restrict the protocol and optionally the
972 ports in an IPsec SA using the rightprotoport and leftprotoport parameters.
980 leftid=@moon.strongswan.org
987 leftid=@moon.strongswan.org
990 conn l2tp # with port wildcard for Mac OS X Panther interoperability
992 rightprotoport=17/%any
994 leftid=@moon.strongswan.org
995 leftprotoport=17/1701
999 rightprotoport=udp/bootpc
1001 leftid=@moon.strongswan.org
1002 leftsubnet=0.0.0.0/0 #allows DHCP discovery broadcast
1003 leftprotoport=udp/bootps
1009 Protocols and ports can be designated either by their numerical values
1010 or by their acronyms defined in /etc/services.
1014 shows the following connection definitions:
1016 "icmp": 192.168.0.1[@moon.strongswan.org]:1/0...%any:1/0
1017 "http": 192.168.0.1[@moon.strongswan.org]:6/80...%any:6/0
1018 "l2tp": 192.168.0.1[@moon.strongswan.org]:17/1701...%any:17/%any
1019 "dhcp": 0.0.0.0/0===192.168.0.1[@moon.strongswan.org]:17/67...%any:17/68
1021 Based on the protocol and port selectors appropriate eroutes will be set
1022 up, so that only the specified payload types will pass through the IPsec
1026 4.6 IPsec policies based on wildcards
1027 ---------------------------------
1029 In large VPN-based remote access networks there is often a requirement that
1030 access to the various parts of an internal network must be granted selectively,
1031 e.g. depending on the group membership of the remote access user. strongSwan
1032 makes this possible by applying wildcard filtering on the VPN user's
1033 distinguished name (ID_DER_ASN1_DN).
1035 Let's make a practical example:
1037 An organization has a sales department (OU=Sales) and a research group
1038 (OU=Research). In the company intranet there are separate subnets for Sales
1039 (10.0.0.0/24) and Research (10.0.1.0/24) but both groups share a common web
1040 server (10.0.2.100). The VPN clients use Virtual IP addresses that are either
1041 assigned statically or via DHCP-over-IPsec. The sales and research departments
1042 use IP addresses from separate DHCP address pools (10.1.0.0/24) and (10.1.1.0/24),
1043 respectively. An X.509 certificate is issued to each employee, containing in its
1044 subject distinguished name the country (C=CH), the company (O=ACME),
1045 the group membership(OU=Sales or OU=Research) and the common name (e.g.
1048 The IPsec policy defined above can now be enforced with the following three
1049 IPsec security associations:
1053 rightid="C=CH, O=ACME, OU=Sales, CN=*"
1054 rightsubnetwithin=10.1.0.0/24 # Sales DHCP range
1055 leftsubnet=10.0.0.0/24 # Sales subnet
1059 rightid="C=CH, O=ACME, OU=Research, CN=*"
1060 rightsubnetwithin=10.1.1.0/24 # Research DHCP range
1061 leftsubnet=10.0.1.0/24 # Research subnet
1065 rightid="C=CH, O=ACME, OU=*, CN=*"
1066 rightsubnetwithin=10.1.0.0/23 # Remote access DHCP range
1067 leftsubnet=10.0.2.100/32 # Web server
1068 rightprotoport=tcp # TCP protocol only
1069 leftprotoport=tcp/http # TCP port 80 only
1071 Of course group specific tunneling could be implemented on the
1072 basis of the Virtual IP range specified by the rightsubnetwithin
1073 parameter alone, but the wildcard matching mechanism guarantees that
1074 only authorized user can access the corresponding subnets.
1076 The '*' character is used as a wildcard in relative distinguished names (RDNs).
1077 In order to match a wildcard template, the ID_DER_ASN1_DN of a peer must contain
1078 the same number of RDNs (selected from the list in section 4.3) appearing in the
1079 exact order defined by the template.
1081 "C=CH, O=ACME, OU=Research, OU=Special Effects, CN=Bart Simpson"
1083 matches the templates
1085 "C=CH, O=ACME, OU=Research, OU=*, CN=*"
1087 "C=CH, O=ACME, OU=*, OU=Special Effects, CN=*"
1089 "C=CH, O=ACME, OU=*, OU=*, CN=*"
1091 but not the template
1093 "C=CH, O=ACME, OU=*, CN=*"
1095 which doesn't have the same number of RDNs.
1098 4.7 IPsec policies based on CA certificates
1099 ---------------------------------------
1101 As an alternative to the wildcard based IPsec policies described in section 4.6,
1102 access to specific client host and subnets can abe controlled on the basis of
1103 the CA that issued the peer certificate
1108 rightca="C=CH, O=ACME, OU=Sales, CN=Sales CA"
1109 rightsubnetwithin=10.1.0.0/24 # Sales DHCP range
1110 leftsubnet=10.0.0.0/24 # Sales subnet
1114 rightca="C=CH, O=ACME, OU=Research, CN=Research CA"
1115 rightsubnetwithin=10.1.1.0/24 # Research DHCP range
1116 leftsubnet=10.0.1.0/24 # Research subnet
1120 rightca="C=CH, O=ACME, CN=ACME Root CA"
1121 rightsubnetwithin=10.1.0.0/23 # Remote access DHCP range
1122 leftsubnet=10.0.2.100/32 # Web server
1123 rightprotoport=tcp # TCP protocol only
1124 leftprotoport=tcp/http # TCP port 80 only
1126 In the example above, the connection "sales" can be used by peers
1127 presenting certificates issued by the Sales CA, only. In the same way,
1128 the use of the connection "research" is restricted to owners of certificates
1129 issued by the Research CA. The connection "web" is open to both "Sales" and
1130 "Research" peers because the required "ACME Root CA" is the issuer of the
1131 Research and Sales intermediate CAs. If no rightca parameter is present
1132 then any valid certificate issued by one of the trusted CAs in
1133 /etc/ipsec.d/cacerts can be used by the peer.
1135 The leftca parameter usually doesn't have to be set explicitly because
1136 by default it is set to the issuer field of the certificate loaded via
1137 leftcert. The statement
1141 sets the CA requested from the peer to the CA used by the left side itself
1147 leftcert=mySalesCert.pem
1150 4.8 Sending certificate requests
1151 ----------------------------
1153 The presence of a rightca parameter also causes the CA to be sent as
1154 part of the certificate request message when strongSwan is the initiator.
1155 A special case occurs when strongSwan responds to a roadwarrior. If several
1156 roadwarrior connections based on different CAs are defined then all eligible
1157 CAs will be listed in Pluto
\92s certificate request message.
1160 4.9 IPsec policies based on group attributes
1161 ----------------------------------------
1163 X.509 attribute certificates are the most powerful mechanism for implementing
1164 IPsec security policies. The rightgroups parameter in a connection definition
1165 restricts the access to members of the listed groups only. An IPsec peer must
1166 have a valid attribute certificate issued by a trusted Authorization Authority
1167 and listing one of the requirede group attributes in order to get admitted.
1172 rightsubnetwithin=10.1.0.0/24 # Sales DHCP range
1173 leftsubnet=10.0.0.0/24 # Sales subnet
1177 rightgroups="Research"
1178 rightsubnetwithin=10.1.1.0/24 # Research DHCP range
1179 leftsubnet=10.0.1.0/24 # Research subnet
1183 rightgroups="Sales, Research"
1184 rightsubnetwithin=10.1.0.0/23 # Remote access DHCP range
1185 leftsubnet=10.0.2.100/32 # Web server
1186 rightprotoport=tcp # TCP protocol only
1187 leftprotoport=tcp/http # TCP port 80 only
1189 In the examples above membership of the group "Sales" is required for
1190 connection sales and membership of "Research" for connection research
1191 whereas connection web is accessible for both groups.
1193 Currently the attribute certificates of the peers must be loaded statically
1194 via the /etc/ipsec.d/acerts/ directory. In future releases of strongSwan it
1195 will be possible to fetch them from an LDAP directory server.
1198 5. Configuring certificates and CRLs
1199 ---------------------------------
1202 5.1 Installing the CA certificates
1203 ------------------------------
1205 X.509 certificates received by strongSwan during the IKE protocol are
1206 automatically authenticated by going up the trust chain until a self-signed
1207 root CA certificate is reached. Usually host certificates are directly signed
1208 by a root CA, but strongSwan also supports multi-level hierarchies with
1209 intermediate CAs in between. All CA certificates belonging to a trust chain
1210 must be copied in either binary DER or base64 PEM format into the directory
1212 /etc/ipsec.d/cacerts/
1215 5.2 Installing optional certificate revocation lists (CRLs)
1216 -------------------------------------------------------
1218 By copying a CA certificate into /etc/ipsec.d/cacerts/, automatically all user
1219 or host certificates issued by this CA are declared valid. Unfortunately
1220 private keys might get compromised inadvertently or intentionally, personal
1221 certificates of users leaving a company have to be blocked immediately, etc.
1222 To this purpose certificate revocation lists (CRLs) have been created. CRLs
1223 contain the serial numbers of all user or host certificates that have been
1224 revoked due to various reasons.
1226 After successful verification of the X.509 trust chain, Pluto searches its
1227 list of CRLs either obtained by loading them from the /etc/ipsec.d/crls/
1228 directory or fetching them dynamically from a HTTP or LDAP server for the
1229 presence of a CRL issued by the CA that has signed the certificate.
1231 If the serial number of the certificate is found in the CRL then the public key
1232 contained in the certificate is declared invalid and the IPSec SA will not be
1233 established. If no CRL is found or if the deadline defined in the nextUpdate
1234 field of the CRL has been reached, a warning is issued but the public key will
1235 nevertheless be accepted. CRLs must be stored either in binary DER or base64 PEM
1236 format in the crls directory. Section 7.3 will explain in detail how CRLs can
1237 be created using OpenSSL.
1240 5.3 Dynamic update of certificates and CRLs
1241 ---------------------------------------
1243 Pluto reads certificates and CRLs from their respective files during system
1244 startup and keeps them in memory in the form of chained lists. X.509
1245 certificates have a finite life span defined by their validity field. Therefore
1246 it must be possible to replace CA or OCSP certificates kept in system memory
1247 without disturbing established ISAKMP SAs. Certificate revocation lists should
1248 also be updated in the regular intervals indicated by the nextUpdate field in
1249 the CRL body. The following interactive commands allow the manual replacement
1250 of the various files:
1252 +---------------------------------------------------------------------------+
1253 | ipsec rereadsecrets reload file /etc/ipsec.secrets |
1254 |---------------------------------------------------------------------------|
1255 | ipsec rereadcacerts reload all files in /etc/ipsec.d/cacerts/ |
1256 |---------------------------------------------------------------------------|
1257 | ipsec rereadaacerts reload all files in /etc/ipsec.d/aacerts/ |
1258 |---------------------------------------------------------------------------|
1259 | ipsec rereadocspcerts reload all files in /etc/ipsec.d/ocspcerts/ |
1260 |---------------------------------------------------------------------------|
1261 | ipsec rereadacerts reload all files in /etc/ipsec.d/acerts/ |
1262 |---------------------------------------------------------------------------|
1263 | ipsec rereadcrls reload all files in /etc/ipsec.d/crls/ |
1264 |---------------------------------------------------------------------------|
1265 | ipsec rereadall ipsec rereadsecrets |
1271 |---------------------------------------------------------------------------|
1272 | ipsec purgeocsp purge the OCSP cache and fetching requests |
1273 +---------------------------------------------------------------------------+
1275 CRLs can also be automatically fetched from an HTTP or LDAP server by using
1276 the CRL distribution points contained in X.509 certificates. The command
1280 shows any pending fetch requests:
1282 Oct 31 00:29:53 2002, trials: 2
1283 issuer: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
1284 distPts: 'http://crl.strongswan.org/strongswan.crl'
1285 'ldap://ldap.strongswan.org/o=Linux strongSwan, c=CH
1286 ?certificateRevocationList?base
1287 ?(objectClass=certificationAuthority)'
1289 In the example above, an http and an ldap URL were extracted from a received
1290 end certificate. An independent thread then tries to fetch a CRL from the
1291 designated distribution points. The same thread also periodically checks
1292 if any loaded CRLs are about to expire. The check interval can be defined in
1293 the "config setup" section of the ipsec.conf file:
1296 crlcheckinterval=600
1298 In our example the thread wakes up every 600 seconds or 10 minutes in order
1299 to check the validity of the CRLs or to retry any pending fetch requests:
1303 Dec 19 09:35:31 2002, revoked certs: 40
1304 issuer: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
1305 distPts: 'http://crl.strongswan.org/strongswan.crl'
1306 updates: this Dec 19 09:35:00 2002
1307 next Dec 19 10:35:00 2002 warning (expires in 19 minutes)
1309 List of fetch requests:
1311 Dec 19 10:15:31 2002, trials: 1
1312 issuer: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
1313 distPts: 'http://crl.strongwan.org/strongswan.crl'
1315 The first trial to update a CRL is started 2*crlcheckinterval before the
1316 nextUpdate time, i.e. when less than 20 minutes are left in our practical
1317 example. When crlcheckinterval is set to 0 (this is also the default value
1318 when the parameter is not set in ipsec.conf) then the CRL checking and updating
1319 thread is not started and dynamic CRL fetching is disabled.
1322 5.4 Local caching of CRLs
1323 ---------------------
1325 The the ipsec.conf option
1330 activates the local caching of CRLs that were dynamically fetched from an
1331 HTTP or LDAP server. Cached copies are stored in /etc/ipsec.d/crls under a
1332 unique filename formed from the issuer's SubjectKeyIdentifier and the suffix .crl.
1334 With the cached copy the CRL is immediately available after pluto's startup.
1335 When the local copy is about to expire it is automatically replaced with an
1336 updated CRL fetched from one of the defined CRL distribution points.
1339 5.5 Online Certificate Status Protocol (OCSP)
1340 -----------------------------------------
1342 The Online Certificate Status Protocol is defined by RFC 2560. It can be
1343 used to query an OCSP server about the current status of an X.509 certificate
1344 and is often used as a more dynamic alternative to a static Certificate
1345 Revocation List (CRL). Both the OCSP request sent by the client and the OCSP
1346 response messages returned by the server are transported via a standard
1347 TCP/HTTP connection. Therefore cURL support must be enabled in pluto/Makefile:
1349 # Uncomment this line to enable OCSP fetching using HTTP
1352 In the simplest OCSP setup, a default URI under which the OCSP server for a
1353 given CA can be accessed is defined in ipsec.conf:
1356 crlcheckinterval=600
1359 cacert=strongswanCert.pem
1360 ocspuri=http://ocsp.strongswan.org:8880
1363 The HTTP port can be freely chosen. In our example we have assumed TCP port 8880.
1364 The crlcheckinterval must be set to a value different from zero. Otherwise the
1365 OCSP fetching thread will not be started.
1367 The well-known openssl-0.9.7 package from http://www.openssl.org implements
1368 an OCSP server that can be used in conjunction with an openssl-based Public
1369 Key Infrastructure. The OCSP client integrated into Pluto does not contain
1370 any OpenSSL code though, but is based on the existing ASN.1 functionality of
1373 The OpenSSL-based OCSP server is started with the following command:
1375 openssl ocsp -index index.txt -CA strongswanCert.pem -port 8880 \
1376 -rkey ocspKey.pem -rsigner ocspCert.pem \
1377 -resp_no_certs -nmin 60 -text
1379 The command consists of the parameters
1381 -index index.txt is a copy of the OpenSSL index file containing the list of
1382 all issued certificates. The certificate status in indext.txt
1383 is designated either by V for valid or R for revoked. If
1384 a new certificate is added or if a certificate is revoked
1385 using the openssl ca command, the OCSP server must be restarted
1386 in order for the changes in index.txt to take effect.
1388 -CA the CA certificate
1390 -port the HTTP port the OCSP server is listening on.
1392 -rkey the private key used to sign the OCSP response. The use of the
1393 sensitive CA private key is not recommended since this could
1394 jeopardize the security of your production PKI if the OCSP
1395 server is hacked. It is much better to generate a special
1396 RSA private key just for OCSP signing use instead.
1398 -rsigner the certificate of the OCSP server containing a public key which
1399 matches the private key defined by -rkey and which can be used by
1400 the client to check the trustworthiness of the signed OCSP response.
1402 -resp_no_certs With this option the OCSP signer certificate defined by
1403 -rsigner is not included in the OCSP response.
1405 -nmin the validity interval of an OCSP response given in minutes.
1406 2*crlcheckinterval before the expiration of the OCSP responses,
1407 a new query will by pro-actively started by the Pluto fetching thread.
1409 If nmin is missing or set to zero then the default validity interval
1410 compiled into Pluto will be 2 minutes, leading to a quasi one-time
1411 use of the OCSP status response which will not be periodically
1412 refreshed by the fetching thread. In conjunction with the parameter
1413 setting "strictcrlpolicy=yes" a real-time certificate status query
1414 can be implemented in this way.
1416 -text This option activates a verbose logging output, showing the contents
1417 of both the received OCSP request and sent OCSP response.
1419 How does Pluto get hold of the OCSP signer certificate? There are two
1422 Either you put the OCSP certificate into the default directory
1424 /etc/ipsec.d/ocspcerts
1426 or alternatively Pluto can receive it as part of the OCSP response from the
1427 remote OCSP server. In the latter case, how can Pluto make sure that
1428 the server has indeed been authorized by the CA to deal out certificate status
1429 information? In order to ascertain the OCSP signer capability, an extended
1430 key usage attribute can be included in the OCSP server certificate. Just
1431 insert the parameter
1433 extendedKeyUsage=OCSPSigner
1435 in the [ usr_cert ] section of your openssl.cnf configuration file before
1436 the CA signs the OCSP server certificate.
1438 For a given CA the corresponding ca section in ipsec.conf (see section 7) allows
1439 to define the URI of a single OCSP server. As an alternative an OCSP URI can be
1440 embedded into each host and user certificate by putting the line
1442 authorityInfoAccess = OCSP;URI:http://ocsp.strongswan.org:8880
1444 into the [ usr_cert ] section of your openssl.cnf configuration file.
1445 If an OCSP authorityInfoAccess extension is present in a certificate then this
1446 record overrides the default URI defined by the ca section.
1452 By default Pluto is quite tolerant concerning the handling of CRLs. It is not
1453 mandatory for a CRL to be present in /etc/ipsec.d/crls and if the expiration
1454 date defined by the nextUpdate field of a CRL has been reached just a warning
1455 is issued but a peer certificate will always be accepted if it has not been
1458 If you want to enforce a stricter CRL policy then you can do this by setting
1459 the "strictcrlpolicy" option. This is done in the "config setup" section
1460 of the ipsec.conf file:
1466 A certificate received from a peer will not be accepted if no corresponding
1467 CRL or OCSP response is available. And if an ISAKMP SA re-negotiation takes
1468 place after the nextUpdate deadline has been reached, the peer certificate
1469 will be declared invalid and the cached RSA public key will be deleted, causing
1470 the connection in question to fail. Therefore if you are going to use the
1471 "strictcrlpolicy=yes" option, make sure that the CRLs will always be updated
1472 in time. Otherwise a total standstill would ensue.
1474 As mentioned earlier the default setting is "strictcrlpolicy=no"
1477 5.7 Configuring the peer side using locally stored certificates
1478 -----------------------------------------------------------
1480 If you don't want to use trust chains based on CA certificates as proposed in
1481 section 4.3 you can alternatively import trusted peer certificates directly
1482 into Pluto. Thus you do not have to rely on the certificate to be transmitted
1483 by the peer as part of the IKE protocol.
1485 With the conn %default section defined in section 4.1 and the use of the
1486 rightcert keyword for the peer side, the connection definitions in section 4.3
1487 can alternatively be written as
1491 rightid=@sun.strongswan.org
1492 rightcert=sunCert.cer
1496 rightcert=carolCert.der
1498 If the peer certificates are loaded locally then there is no sense in sending
1499 any certificates to the other end via the IKE Main Mode protocol. Especially
1500 if self-signed certificates are used which wouldn't be accepted any way by
1501 the other side. In these cases it is recommended to add
1505 to the connection definition[s] in order to avoid the sending of the host's
1506 own certificate. The default value is
1508 leftsendcert=always.
1510 If a peer certificate contains a subjectAltName extension, then an alternative
1511 rightid type can be used, as the example "conn sun" shows. If no rightid
1512 entry is present then the subject distinguished name contained in the
1513 certificate is taken as the ID.
1515 Using the same rules concerning pathnames that apply to strongSwan's own
1516 certificates, the following two definitions are also valid for trusted peer
1519 rightcert=peercerts/carolCert.der
1523 rightcert=/usr/ssl/certs/carolCert.der
1526 6. Installing the private key - ipsec.secrets
1527 ------------------------------------------
1529 6.1 Loading private key files in PKCS#1 format
1530 ------------------------------------------
1532 Besides strongSwan's raw private key format strongSwan has been enabled to
1533 load RSA private keys in the PKCS#1 file format. The key files can be
1534 optionally secured with a passphrase.
1536 RSA private key files are declared in /etc/ipsec.secrets using the syntax
1538 : RSA <my keyfile> "<optional passphrase>"
1540 The key file can be either in base64 PEM-format or binary DER-format. The
1541 actual coding is detected "automagically" by Pluto. The example
1545 uses a relative pathname. In this case Pluto will look for the key file
1548 /etc/ipsec.d/private
1550 As an alternative an absolute pathname can be given as in
1552 : RSA /usr/ssl/private/moonKey.pem
1554 In both cases make sure that the key files are root readable only.
1556 Often a private key must be transported from the Certification Authority
1557 where it was generated to the target security gateway where it is going
1558 to be used. In order to protect the key it can be encrypted with 3DES
1559 using a symmetric transport key derived from a cryptographically strong
1562 openssl genrsa -des3 -out moonKey.pem 1024
1564 Because of the weak security, key files protected by single DES will not
1565 be accepted by Pluto!!!
1567 Once on the security gateway the private key can either be permanently
1568 unlocked so that it can be used by Pluto without having to know a
1571 openssl rsa -in moonKey.pem -out moonKey.pem
1573 or as an option the key file can remain secured. In this case the passphrase
1574 unlocking the private key must be added after the pathname in
1577 : RSA moonKey.pem "This is my passphrase"
1579 Some CAs distribute private keys embedded in a PKCS#12 file. Since Pluto
1580 is not able yet to read this format directly, the private key part must
1581 first be extracted using the command
1583 openssl pkcs12 -nocerts -in moonCert.p12 -out moonKey.pem
1585 if the key file moonKey.pem is to be secured again by a passphrase, or
1587 openssl pkcs12 -nocerts -nodes -in moonCert.p12 -out moonKey.pem
1589 if the private key is to be stored unlocked.
1592 6.2 Entering passphrases interactively
1593 ----------------------------------
1595 On a VPN gateway you would want to put the passphrase protecting the private
1596 key file right into /etc/ipsec.secrets as described in the previous paragraph,
1597 so that the gateway can be booted in unattended mode. The risk of keeping
1598 unencrypted secrets on a server can be minimized by putting the box into a
1599 locked room. As long as no one can get root access on the machine the private
1602 On a mobile laptop computer the situation is quite different. The computer can
1603 be stolen or the user is leaving it unattended so that unauthorized persons
1604 can get access to it. In theses cases it would be preferable not to keep any
1605 passphrases openly in /etc/ipsec.secrets but to prompt for them interactively
1606 instead. This is easily done by defining
1608 : RSA moonKey.pem %prompt
1610 Since strongSwan is usually started during the boot process, usually no
1611 interactive console windows is available which can be used by Pluto to
1612 prompt for the passphrase. This must be initiated by the user by typing
1616 which actually is an alias for the existing command
1620 and which causes the prompt
1622 need passphrase for '/etc/ipsec.d/private/moonKey.pem'
1625 to appear. If the passphrase was correct and the private key file could be
1626 successfully decrypted then
1630 results. Otherwise the prompt
1632 invalid passphrase, please try again
1635 will give you another try. Entering a carriage return will abort the
1636 the passphrase prompting.
1639 6.3 Multiple private keys
1640 ---------------------
1642 strongSwan supports multiple private keys. Since the connections defined
1643 in ipsec.conf can find the correct private key based on the public key
1644 contained in the certificate assigned by leftcert, default private key
1645 definitions without specific IDs can be used
1647 : RSA myKey1.pem "<optional passphrase1>"
1649 : RSA myKey2.pem "<optional passphrase2>"
1652 7. Configuring CA properties - ipsec.conf
1653 --------------------------------------
1655 Besides the definition of IPsec connections the ipsec.conf file can also
1656 be used to configure a few properties of the certification authorities
1657 needed to establish the X.509 trust chains. The following example shows
1658 the parameters that are currently available:
1661 cacert=strongswanCert.pem
1662 ocspuri=http://ocsp.strongswan.org:8880
1663 crluri=http://crl.strongswan.org/strongswan.crl'
1664 crluri2="ldap:///O=Linux strongSwan, C=CH?certificateRevocationList"
1665 ldaphost=ldap.strongswan.org
1668 In a similar way as conn sections are used for connection definitions, an
1669 arbitrary number of optional ca sections define the basic properties of CAs.
1671 Each ca section is named with a unique label
1675 The only mandatory parameter is
1677 cacert=strongswanCert.pem
1679 which points to the CA certificate which usually resides in the default
1680 directory /etc/ipsec.d/cacerts/ but could also be retrieved via an absolute
1681 path name. If the CA certificate is stored on a smartcard then the
1684 cacert=%smartcard#<n>
1688 cacert=%smartcard<optional slot nr>:<key id>
1690 can be used. The selection of smartcard slots is described in more detail
1693 From the certificate the CA's distinguished name and the serial number
1694 is extracted. If an optional subjectKeyAuthentifier is present then it can
1695 be used to uniquely identify consecutive generations of CA certificates
1696 carrying the same distinguished name.
1700 ocspuri=http://ocsp.strongswan.org:8880
1702 allows to define an individual OCSP server per CA. Also up to two additional
1703 CRL distribution points (CDPs) can be defined
1705 crluri=http://crl.strongswan.org/strongswan.crl'
1706 crluri2="ldap:///O=Linux strongSwan, C=CH?certificateRevocationList"
1708 which are added to any CDPs already present in the received certificates
1709 themselves. The last parameter
1711 ldaphost=ldap.strongswan.org
1713 can be used to fill in the actual server name in LDAP CDPs where the host is missing
1714 as e.g. in the crluri2 above. In future releases this ldaphost parameter might be used
1715 to retrieve user, host and attribute certificates.
1718 With the auto=add statement the ca definition is automatically loaded into Pluto during
1719 system startup. Setting auto=ignore will ignore the ca section. Additional ca definitions
1720 can be loaded from ipsec.conf during runtime with the command
1722 ipsec auto --type ca --add strongswan-sales
1726 ipsec auto --type ca --delete strongswan-sales
1728 deletes the labeled ca entry. And finally the command
1730 ipsec auto --type ca --replace strongswan
1732 first deletes the old definition in Pluto's memory and then loads the updated version
1733 from ipsec.conf. Any parameters which appear in several ca definitions can be put in
1734 a common ca %default section
1737 ldaphost=ldap.strongswan.org
1740 8. Smartcard support
1743 8.1 Configuring a smartcard-based connection
1744 ----------------------------------------
1746 Defining a smartcard-based connection in ipsec.conf is easy:
1750 rightid=@sun.strongswan.org
1755 In most cases there is a single smartcard reader or cryptotoken and only one
1756 RSA private key safely stored on the crypto device. Thus usually the entry
1760 which stands for the full notation
1762 leftcert=%smartcard#1
1764 is sufficient where the first certificate/private key object enumerated by
1765 the PKCS#11 module is used. If several certificate/private key objects are
1766 present then the nth object can be selected using
1768 leftcert=%smartcard#<n>
1774 gives an overview over all certificate objects made available by the PKCS#11
1775 module.CA certificates are automatically available as trust anchors.
1777 As an alternative the certificate ID and/or the slot number defined by
1778 the PKCS#11 standard can be specified using the notation
1780 leftcert=%smartcard<optional slot nr>:<key id in hex format>
1784 leftcert=%smartcard:50
1786 will look in all available slots for ID 0x50 starting with the first slot
1787 (usually slot 0) whereas
1789 leftcert=%smartcard4:50
1791 will directly check slot 4 (which is usually the first slot on the second
1792 reader/token when using the OpenSC library) for a key with ID 0x50.
1795 8.2 Entering the PIN code
1796 ---------------------
1798 Since the smartcard signing operation needed to sign the hash with the
1799 RSA private key during IKE Main Mode is protected by a PIN code,
1800 the secret PIN must be made available to Pluto.
1802 For gateways that must be able to start IPsec tunnels automatically in
1803 unattended mode after a reboot, the secret PIN can be stored statically
1806 : PIN %smartcard "12345678"
1808 or with the general notation
1810 : PIN %smartcard#<n> "<PIN code>"
1814 : PIN %smartcard<optional slot nr>:<key id> "<PIN code>"
1816 On personal notebooks that could get stolen, you wouldn't want to store
1817 your PIN in ipsec.secrets. Thus the alternative form
1819 : PIN %smartcard %prompt
1821 will prompt you for the PIN when you start up the first IPsec connection
1826 The auto command calls the whack function which in turn communicates with
1827 Pluto over a socket. Since the whack function call is executed from a command
1828 window, Pluto can prompt you for the PIN over this socket connection.
1829 Unfortunately roadwarrior connections which just wait passively for peers
1830 cannot be initiated via the command window:
1835 leftcert=%smartcard4:50
1838 But if there is a corresponding entry
1840 : PIN %smartcard4:50 %prompt
1842 in ipsec.secrets, then the standard command
1850 can be used to enter the PIN code for this connection interactively.
1856 can be executed at any time to check the current status of the PIN code[s].
1859 8.3 PIN-pad equipped smartcard readers
1860 ----------------------------------
1862 Smartcard readers with an integrated PIN-pad offer an increased security
1863 level because the PIN entry cannot be sniffed on the host computer e.g.
1864 by a surrepticiously installed key logger. In order to tell pluto not to
1865 prompt for the PIN on the host itself, the entry
1867 : PIN %smartcard:50 %pinpad
1869 can be used in ipsec.secrets. Because the key pad does not cache the PIN in
1870 the smartcard reader, it must be entered for every PKCS #11 session login.
1871 By default pluto does a session logout after every RSA signature. In order
1872 to avoid the repeated entry of the PIN code during the periodic IKE main
1873 mode rekeyings, the following parameter can be set in the config setup
1874 section of ipsec.conf:
1879 The default setting is pkcs11keepstate=no.
1882 8.4 Configuring a smartcard with pkcsc15-init
1883 -----------------------------------------
1885 strongSwan's smartcard solution is based on the PKCS#15 "Cryptographic Token
1886 Information Format Standard" fully supported by OpenSC library functions.
1889 pkcs15-init --erase-card --create-pkcs15
1891 a fresh PKCS#15 file structure is created on a smartcard or cryptotoken.
1892 With the next command
1894 pkcs15-init --auth-id 1 --store-pin --pin "12345678" --puk "87654321"
1897 a secret PIN code with auth-id 1 is stored in an unretrievable location on
1898 the smart card. The PIN will protect the RSA signing operation. If the PIN
1899 is entered incorrectly more than three times the smartcard will be locked
1900 and the PUK code can be used to unlock the card again.
1902 Next the RSA private key is transferred to the smartcard
1904 pkcs15-init --auth-id 1 --store-private-key myKey.pem [--id 45]
1906 By default the PKCS#15 smartcard record will be assigned the id 45.
1907 Using the --id option multiple key records can be stored on a smartcard.
1909 At last we load the matching X.509 certificate onto the smartcard
1911 pkcs15-init --auth-id 1 --store-certificate myCert.pem [--id 45]
1913 The pkcs15-tool can now be used to verify the contents of the smartcard.
1915 pkcs15-tool --list-pins --list-keys --list-certificates
1917 If everything is ok then you are ready to use the generated PKCS#15
1918 structure with strongSwan.
1920 8.5 PKCS#11 proxy functions
1921 -----------------------
1923 With the setting pkcs11keepstate=yes some PKCS#11 implementations
1924 (e.g. OpenSC) will lock the access to the smartcard as soon as pluto has
1925 opened a session and will thus prevent other application from sharing the
1926 smartcard resource. In order to solve this locking problem, strongSwan
1927 offers a PKCS#11 proxy service making use of the whack socket communication
1928 channel. The setting
1933 will enable the proxy mode that is disabled by default.
1935 Currently two smartcard operations are supported: RSA encryption and
1936 RSA decryption. The notation is as follows:
1938 ipsec scdecrypt <encrypted data>
1939 [--inbase 16|hex|64|base64|256|text|ascii]
1940 [--outbase 16|hex|64|base64|256|text|ascii]
1943 The default settings for inbase and outbase is hexadecimal.
1944 Thus the simplest call has the form
1946 ipsec scdecrypt bb952b71920094ce0696ef9b8b26...12e6
1948 and the returned result might be a decrypted 128 bit AES key
1950 000 8836362e030e6707c32ffaa0bdad5540
1952 The leading three characters represent the return code of the whack channel
1953 with 000 signifying that no error has occured. Here is another example showing
1954 the use of the inbase and outbase attributes
1956 ipsec scdecrypt m/ewDnTs0k...woE= --inbase base64 --outbase text
1958 where the result has the form
1960 000 This is a secret
1962 By default the first RSA private key found by the PKCS#11 enumeration is
1963 used. If a different key should be selected then the notation introduced
1964 in sections 8.1 and 8.2 can be used:
1966 --keyid %smartcard:50
1967 --keyid %smartcard4:50
1968 --keyid %smartcard#3
1970 with --keyid %smartcard#1 being the default. If supported by the smartcard
1971 and PKCS#11 library RSA encryption can be used with the notation
1973 ipsec scencrypt <plaintext data>
1974 [--inbase 16|hex|64|base64|256|text|ascii]
1975 [--outbase 16|hex|64|base64|256|text|ascii]
1980 ipsec scencrypt "This is a secret" --inbase ascii --outbase 64
1982 returning the expected output
1984 000 m/ewDnTs0k...woE=
1987 9. Configuring the clients
1988 -----------------------
1993 A strongSwan to strongSwan connection is symmetrical. Any of the four defined
1994 ID types can be used, even different types on either end of the connection,
1995 although this wouldn't make much sense.
1997 +--------------------------------------------------------------+
1998 | Connection Definition ID type subjectAltName |
1999 |--------------------------------------------------------------|
2000 | rightid (strongSwan) DER_ASN1_DN - |
2002 | USER_FQDN email: |
2004 |--------------------------------------------------------------|
2005 | leftid (strongSwan) DER_ASN1_DN - |
2007 | USER_FQDN email: |
2009 +--------------------------------------------------------------+
2015 Use the file peerCert.p12 to import PGPnet's X.509 certificate, the CA
2016 certificate, plus the encrypted private key in binary PKCS#12 format into the
2017 PGPkey tool. You will be prompted for the passphrase securing the private key.
2019 Use the file myCert.pem to import the X.509 certificate of the strongSwan
2020 security gateway into the PGPkey tool. The PGPkeyTool does not accept X.509
2021 certificates in binary DER format, so it must be imported in base64 format:
2023 -----BEGIN CERTIFICATE-----
2027 -----END CERTIFICATE-----
2029 Make sure that there is no human-readable listing of the X.509 certificate in
2032 -----BEGIN CERTIFICATE-----
2034 otherwise PGPnet will refuse to load the *.PEM file. Any surplus lines can
2035 either be deleted by loading the certificate into a text editor or you can
2038 openssl x509 -in myCert.pem -out myCert.pem
2040 to achieve the same effect.
2042 With authentication based on X.509 certificates, PGPnet always sends the ID
2043 type DER_ASN1_DN, therefore rightid in the connection definition of the
2044 strongSwan security gateway must be an ASN.1 distinguished name.
2046 In the receiving direction PGPnet accepts all four ID types from strongSwan.
2048 +--------------------------------------------------------------+
2049 | Connection Definition ID type subjectAltName |
2050 |--------------------------------------------------------------|
2051 | rightid (PGPnet) DER_ASN1_DN - |
2052 |--------------------------------------------------------------|
2053 | leftid (strongSwan) DER_ASN1_DN - |
2055 | USER_FQDN email: |
2057 +--------------------------------------------------------------+
2060 9.3 SafeNet/Soft-PK/Soft-Remote
2061 ---------------------------
2063 SafeNet/Soft-PK and SafeNet/Soft-Remote can be configured to send their
2064 identity either as DER_ASN1_DN, IPV4_ADDR, FQDN, or USER_FQDN.
2065 In the receiving direction SafeNet/Soft-PK and SafeNet/Soft-Remote
2066 accept all four ID types coming from strongSwan.
2068 +--------------------------------------------------------------+
2069 | Connection Definition ID type subjectAltName |
2070 |--------------------------------------------------------------|
2071 | rightid (SafeNet/Soft-PK) DER_ASN1_DN - |
2073 | USER_FQDN email: |
2075 |--------------------------------------------------------------|
2076 | leftid (strongSwan) DER_ASN1_DN - |
2078 | USER_FQDN email: |
2080 +--------------------------------------------------------------+
2086 SSH Sentinel sends its identity as DER_ASN1_DN if the subjectAltName field of
2087 its certificate is empty. If a subjectAltName field is present, then the
2088 corresponding type IPV4_ADDR, FQDN, or USER_FQDN is automatically chosen.
2089 With several subjectAltName entries, the precedence of the different ID types
2090 is not quite clear. In the receiving direction SSH Sentinel accepts all four
2091 ID types from strongSwan.
2093 +--------------------------------------------------------------+
2094 | Connection Definition ID type subjectAltName |
2095 |--------------------------------------------------------------|
2096 | rightid (SSH Sentinel) DER_ASN1_DN - |
2098 | USER_FQDN email: |
2100 |--------------------------------------------------------------|
2101 | leftid (strongSwan) DER_ASN1_DN - |
2103 | USER_FQDN email: |
2105 +--------------------------------------------------------------+
2111 Windows 2000 and Windows XP always send the ID type DER_ASN1_DN,
2112 therefore rightid in the connection definition of the strongSwan
2113 security gateway must be an ASN.1 distinguished name.In the
2114 receiving direction Windows 2000/XP accepts all four ID types
2117 +--------------------------------------------------------------+
2118 | Connection Definition ID type subjectAltName |
2119 |--------------------------------------------------------------|
2120 | rightid (Windows 2000/XP) DER_ASN1_DN - |
2121 |--------------------------------------------------------------|
2122 | leftid (strongSwan) DER_ASN1_D - |
2124 | USER_FQDN email: |
2126 +--------------------------------------------------------------+
2129 10. Monitoring functions
2130 --------------------
2132 strongSwan offers the following monitoring functions:
2137 lists all IKE and ESP cryptographic algorithms that are currently
2138 registered with strongSwan.
2140 The a listing has the following form:
2142 List of registered IKE Encryption Algorithms:
2144 #3 OAKLEY_BLOWFISH_CBC, blocksize: 64, keylen: 128-128-256
2145 #5 OAKLEY_3DES_CBC, blocksize: 64, keylen: 192-192-192
2146 #7 OAKLEY_AES_CBC, blocksize: 128, keylen: 128-128-256
2147 #65004 OAKLEY_SERPENT_CBC, blocksize: 128, keylen: 128-128-256
2148 #65005 OAKLEY_TWOFISH_CBC, blocksize: 128, keylen: 128-128-256
2149 #65289 OAKLEY_TWOFISH_CBC_SSH, blocksize: 128, keylen: 128-128-256
2151 List of registered IKE Hash Algorithms:
2153 #1 OAKLEY_MD5, hashsize: 128
2154 #2 OAKLEY_SHA, hashsize: 160
2155 #4 OAKLEY_SHA2_256, hashsize: 256
2156 #6 OAKLEY_SHA2_512, hashsize: 512
2158 List of registered IKE DH Groups:
2160 #2 OAKLEY_GROUP_MODP1024, groupsize: 1024
2161 #5 OAKLEY_GROUP_MODP1536, groupsize: 1536
2162 #14 OAKLEY_GROUP_MODP2048, groupsize: 2048
2163 #15 OAKLEY_GROUP_MODP3072, groupsize: 3072
2164 #16 OAKLEY_GROUP_MODP4096, groupsize: 4096
2165 #17 OAKLEY_GROUP_MODP6144, groupsize: 6144
2166 #18 OAKLEY_GROUP_MODP8192, groupsize: 8192
2168 List of registered ESP Encryption Algorithms:
2170 #3 ESP_3DES, blocksize: 64, keylen: 168-168
2171 #7 ESP_BLOWFISH, blocksize: 64, keylen: 96-128
2172 #12 ESP_AES, blocksize: 128, keylen: 128-256
2173 #252 ESP_SERPENT, blocksize: 128, keylen: 128-256
2174 #253 ESP_TWOFISH, blocksize: 128, keylen: 128-256
2176 List of registered ESP Authentication Algorithms:
2178 #1 AUTH_ALGORITHM_HMAC_MD5, keylen: 128-128
2179 #2 AUTH_ALGORITHM_HMAC_SHA1, keylen: 160-160
2180 #5 AUTH_ALGORITHM_HMAC_SHA2_256, keylen: 256-256
2181 #7 AUTH_ALGORITHM_HMAC_SHA2_512, keylen: 512-512
2186 ipsec listpubkeys [--utc]
2188 lists all public keys currently installed in the chained list of public
2189 keys. These keys were statically loaded from ipsec.conf or aquired either
2190 from received certificates or retrieved from secure DNS servers using
2193 The public key listing has the following form:
2195 Feb 11 14:40:18 2005, 2048 RSA Key AwEAAa+uL,
2196 until Sep 09 13:17:25 2009 ok
2197 ID_FQDN '@moon.strongswan.org'
2198 issuer: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
2200 Feb 11 14:40:18 2005, 2048 RSA Key AwEAAa+uL,
2201 until Sep 09 13:17:25 2009 ok
2202 ID_DER_ASN1_DN 'C=CH, O=Linux strongSwan, CN=moon.strongswan.org'
2203 issuer: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
2205 Feb 11 13:36:53 2005, 2048 RSA Key AwEAAbgbh,
2206 until Dec 31 22:43:18 2009 ok
2207 ID_USER_FQDN 'carol@strongswan.org'
2208 issuer: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
2213 - the date the public key was installed either in local time or UTC (--utc)
2214 - the modulus size of the RSA key in bits
2215 - a keyID consisting of 9 base64 symbols representing the public exponent
2216 and the most significant bits of the modulus
2217 - the expiration date of the public key (extracted from the certificate)
2218 - the type and value of the ID associated with the public key.
2219 - the issuer of the certificate the public key was extracted from.
2220 - the serial number of the certificate the public key was extracted from.
2222 A public key can be associated with several IDs, e.g. using subjectAltNames
2223 in certificates and an ID can possess several public keys, e.g. retrieved
2224 from a secure DNS server.
2229 ipsec listcerts [--utc]
2231 lists all local certificates, both strongSwan's own and those of
2232 trusted peer loaded via leftcert and rightcert, respectively.
2234 The output has the form
2236 Feb 11 13:36:47 2005, count: 4
2237 subject: 'C=CH, O=Linux strongSwan, CN=moon.strongswan.org'
2238 issuer: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
2240 pubkey: 2048 RSA Key AwEAAa+uL, has private key
2241 validity: not before Sep 10 13:17:25 2004 ok
2242 not after Sep 09 13:17:25 2009 ok
2243 subjkey: e5:e4:10:87:6c:2a:c4:be:ad:85:49:42:a6:de:76:58:30:3a:9f:c1
2244 authkey: 5d:a7:dd:70:06:51:32:7e:e7:b6:6d:b3:b5:e5:e0:60:ea:2e:4d:ef
2249 - the date the certificate was installed either in local time or UTC (--utc)
2250 - the count shows how many connections refer to this certificate
2251 - the subject of the certificate
2252 - the issuer of the certificate
2253 - the serial number of the certificate
2254 - the size and keyid of the RSA public key contained in the certificate.
2255 the label "has private key" indicates that a matching RSA private key
2256 has been found, defined or loaded in ipsec.secrets.
2257 - the label "on smartcard" indicates that the certificate was loaded from
2258 a smartcard or cryptotoken and that most probably a matching RSA private
2259 key also resides on-card.
2260 - the validity of the CA certificate expressed either in local time or
2261 UTC (--utc). The validity is checked automatically resulting either
2262 in an "ok" message or a "fatal" error message.
2263 - the optional subjectKeyIdentifier extension which is a 20 byte SHA-1 hash
2264 over the certificate's public key.
2265 - the optional authorityKeyIdentifier extension which is a 20 byte SHA-1 hash
2266 over the public key of the issuer who signed the certificate.
2267 - the serial number of the issuer's certificate.
2272 ipsec listcacerts [--utc]
2274 lists all CA certificates that have been either been loaded from the directory
2275 /etc/ipsec.d/cacerts/ or received via the IKE protocol. The output has the form
2277 Feb 11 13:36:52 2005, count: 1
2278 subject: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
2279 issuer: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
2281 pubkey: 2048 RSA Key AwEAAb/yX
2282 validity: not before Sep 10 13:01:45 2004 ok
2283 not after Sep 08 13:01:45 2014 ok
2284 subjkey: 5d:a7:dd:70:06:51:32:7e:e7:b6:6d:b3:b5:e5:e0:60:ea:2e:4d:ef
2285 authkey: 5d:a7:dd:70:06:51:32:7e:e7:b6:6d:b3:b5:e5:e0:60:ea:2e:4d:ef
2290 - the date the CA certificate was installed either in local time or UTC (--utc)
2291 - the count is always set to 1
2292 - the subject of the CA certificate
2293 - the issuer of the CA certificate
2294 - the serial number of the CA certificate
2295 - the size and keyid of the RSA public key contained in the certificate.
2296 - the validity of the CA certificate expressed either in local time or
2297 UTC (--utc). The validity is checked automatically resulting either
2298 in an "ok" message or a "fatal" error message.
2299 - the optional subjectKeyIdentifier extension which is a 20 byte SHA-1 hash
2300 over the CA certificate's public key.
2301 - the optional authorityKeyIdentifier extension which is a 20 byte SHA-1 hash
2302 over the public key of the issuer who signed the CA certificate.
2303 For Root CA certificates the authorityKeyIdentifier and subjectKeyIdentifier
2304 fields must be equal.
2305 - the serial number of the issuer's certificate.
2310 ipsec listaacerts [--utc]
2312 lists all Authorization Authority certificates that have been loaded from
2313 the directory /etc/ipsec.d/aacerts/.
2314 The output has the form
2316 Dec 20 13:29:55 2004, count: 1
2317 subject: 'C=CH, O=strongSec GmbH, CN=strongSec Authorization Authority'
2318 issuer: 'C=CH, O=strongSec GmbH, CN=strongSec Root CA'
2320 pubkey: 2048 RSA Key AwEAAfazH
2321 validity: not before Aug 24 13:41:56 2003 ok
2322 not after Aug 23 13:41:56 2005 ok
2323 subjkey: 56:89:b9:28:c9:1b:a0:00:7f:50:9d:ec:28:75:23:c1:1e:d1:dd:90
2324 authkey: af:80:d5:c6:02:1c:96:78:b3:85:a5:65:a2:23:fd:ad:cf:e2:55:b2
2329 - the date the AA certificate was installed either in local time or UTC (--utc)
2330 - the count is always set to 1
2331 - the subject of the AA certificate
2332 - the issuer of the AA certificate
2333 - the serial number of the AA certificate
2334 - the size and keyid of the RSA public key contained in the certificate.
2335 - the validity of the AA certificate expressed either in local time or
2336 UTC (--utc). The validity is checked automatically resulting either
2337 in an "ok" message or a "fatal" error message.
2338 - the optional subjectKeyIdentifier extension which is a 20 byte SHA-1 hash
2339 over the AA certificate's public key.
2340 - the optional authorityKeyIdentifier extension which is a 20 byte SHA-1 hash
2341 over the public key of the issuer who signed the AA certificate.
2342 - the serial number of the issuer's certificate.
2347 ipsec listocspcerts [--utc]
2349 lists all OCSO signer certificates that have been either loaded from
2350 /etc/ipsec.d/ocspcerts/ or have been received included in the OCSP server
2351 response. The output has the form
2353 Feb 09 22:56:17 2005, count: 1
2354 subject: 'C=CH, O=Linux strongSwan, OU=OCSP, CN=ocsp.strongswan.org'
2355 issuer: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
2357 pubkey: 2048 RSA Key AwEAAaonT
2358 validity: not before Nov 19 17:29:28 2004 ok
2359 not after Nov 18 17:29:28 2009 ok
2360 subjkey: 88:07:0a:b8:ae:c7:c1:07:5c:be:68:6a:c4:a5:7f:81:1f:37:b5:56
2361 authkey: 5d:a7:dd:70:06:51:32:7e:e7:b6:6d:b3:b5:e5:e0:60:ea:2e:4d:ef
2366 - the date the OCSP signer certificate was installed either in local time
2368 - the count is always set to 1
2369 - the subject of the OCSP signer certificate
2370 - the issuer of the OCSP signer certificate
2371 - the serial number of the OCSP signer certificate
2372 - the size and keyid of the RSA public key contained in the certificate.
2373 - the validity of the OCSP signer certificate expressed either in local time
2374 or UTC (--utc). The validity is checked automatically resulting either
2375 in an "ok" message or a "fatal" error message.
2376 - the optional subjectKeyIdentifier extension which is a 20 byte SHA-1 hash
2377 over the OCSP signer certificate's public key.
2378 - the optional authorityKeyIdentifier extension which is a 20 byte SHA-1 hash
2379 over the public key of the issuer who signed the OCSP certificate.
2380 - the serial number of the issuer's certificate.
2385 ipsec listacerts [--utc]
2387 lists all X.509 attribute certificates that have been loaded from the directory
2388 /etc/ipsec.d/acerts/.
2389 The output has the form
2391 Dec 20 13:29:56 2004
2392 holder: 'C=CH, O=strongSec GmbH, CN=Andreas Steffen'
2393 hissuer: 'C=CH, O=strongSec GmbH, CN=strongSec Root CA'
2395 groups: Research, Sales
2396 issuer: 'C=CH, O=strongSec GmbH, CN=strongSec Authorization Authority'
2398 validity: not before Dec 19 14:51:38 2004 ok
2399 not after Dec 20 14:51:38 2004 fatal (expired)
2400 authkey: 56:89:b9:28:c9:1b:a0:00:7f:50:9d:ec:28:75:23:c1:1e:d1:dd:90
2405 - the date the attribute certificate was installed either in local time
2407 - the holder of the attribute certificate
2408 - the issuer of holder's certificate
2409 - the serial number of the holder's certificate
2410 - the group attributes
2411 - the issuing Authorization Authority of the attribute certificate
2412 - the serial number of the attribute certificate
2413 - the validity of the attribute certificate expressed either in local time or
2414 UTC (--utc). The validity is checked automatically resulting either
2415 in an "ok" message or a "fatal" error message.
2416 - an authorityKeyIdentifier extension which is a 20 byte SHA-1 hash
2417 over the public key of the issuing Authorization Authority
2418 - the serial number of the AA certificate.
2423 ipsec listgroups [--utc]
2425 lists all group attributes either defined in right|leftgroups statements
2426 in ipsec.conf or contained in loaded X.509 attribute certificates.
2427 The output has the form
2429 Dec 20 13:29:55 2004, count: 4
2431 Dec 20 13:30:04 2004, count: 1
2433 Dec 20 13:29:55 2004, count: 3
2438 - the date the group attribute was first installed either in local time
2440 - the count shows how many times the attribute is used
2446 ipsec listcainfos [--utc]
2448 lists the properties defined by the ca definition sections in ipsec.conf.
2449 The output has the form
2451 Jun 08 22:31:37 2004, "strongswan"
2452 authname: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
2453 ldaphost: 'ldap.strongswan.org'
2454 ocspuri: 'http://ocsp.strongswan.org:8880'
2455 distPts: 'http://crl.strongswan.org/strongswan.crl'
2456 'ldap:///O=Linux strongSwan, C=CH?certificateRevocationList'
2457 authkey: 5d:a7:dd:70:06:51:32:7e:e7:b6:6d:b3:b5:e5:e0:60:ea:2e:4d:ef
2462 - the date the CA definition was loaded either in local time or UTC (--utc)
2463 - the name of the ca section
2464 - the distinguished name of the CA
2465 - an optional default ldap host for the CA
2466 - an optional OCSP URI
2467 - a maximum of two optional CRL distribution points
2468 - the optional authorityKeyIdentifier extension which is a 20 byte SHA-1 hash
2469 over the public key of the CA.
2470 - the serial number of the CA.
2475 ipsec listcrls [--utc]
2477 lists all CRLs that have been loaded from /etc/ipsec.d/crls/.
2478 The output has the form
2480 Feb 11 13:37:00 2005, revoked certs: 1
2481 issuer: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
2482 distPts: 'http://crl.strongswan.org/strongswan.crl'
2483 updates: this Feb 08 07:46:29 2005
2484 next Mar 10 07:46:29 2005 ok
2485 authkey: 5d:a7:dd:70:06:51:32:7e:e7:b6:6d:b3:b5:e5:e0:60:ea:2e:4d:ef
2490 - the date the CRL was installed either in local time or UTC (--utc)
2491 - the number revoked certificates
2492 - the issuer of the CRL
2493 - the URLs of the distribution points where the CRL can be fetched from.
2494 - the dates when the CRL was issued and when the next update
2495 is expected, respectively, expressed either in local time or
2496 UTC (--utc). It is automatically checked if the next update
2497 deadline has passed, resulting either in an "ok" message, a
2498 a "warning" message when strictcrlpolicy=no or a "fatal" message when
2499 strictcrlpolicy=yes.
2500 - the optional authorityKeyIdentifier extension which is a 20 byte SHA-1 hash
2501 over the public key of the issuer who signed the CRL. This extension is
2502 present in version 2 CRLs, only.
2503 - the serial number of the issuer's certificate.
2509 ipsec listocsp [--utc]
2511 lists the contents of the OCSP response cache. The output has the form
2513 issuer: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
2514 uri: 'http://ocsp.strongswan.org:8880'
2515 authname: 13:9d:a0:9e:f4:32:ab:8f:e2:89:56:67:fa:d0:d4:e3:35:86:71:b9
2516 authkey: 5d:a7:dd:70:06:51:32:7e:e7:b6:6d:b3:b5:e5:e0:60:ea:2e:4d:ef
2518 Feb 09 22:56:17 2005, until Feb 09 23:01:17 2005 warning (expires in 4 minutes)
2523 - the distinguished name of the CA handled by the OCSP server
2524 - the http URI of the OCSP server.
2525 - the 20 byte SHA-1 hash of the CA's distinguished name
2526 - the 20 byte SHA-1 hash of the CA's public key
2527 - the serial number of the CA's certificate
2528 - a certificate status list showing
2529 - the time the OCSP status was received
2530 - an optional nextUpdate deadline (if missing the OCSP status will be
2531 onetime with a lifetime of 2 minutes only).
2532 - the serial number of the certificate
2533 - the status of the certificate (good, revoked, unknown)
2538 ipsec listcards [--utc]
2540 lists all smartcard records that are currently in use by Pluto.
2541 The output has the form
2543 Aug 17 16:47:59 2005, #1, count: 6
2544 slot: 0, session closed, logged out, has valid pin
2547 subject: 'C=CH, O=Linux strongSwan, CN=carol@strongswan.org'
2549 with pkcs11keepstate=no and
2551 Aug 17 16:47:59 2005, #1, count: 6
2552 slot: 0, session opened, logged in, has pin pad
2555 subject: 'C=CH, O=Linux strongSwan, CN=carol@strongswan.org'
2557 with pkcs11keepstate=yes and shows
2559 - the date the certificate was read from the smartcard record
2560 - the certificate objects are numbered starting from #1
2561 - the count shows how many connections and secret pin entries point
2562 to the smartcard record
2563 - the PKCS #11 slot number
2564 - the PKCS #11 session state: closed | opened
2565 - the PKCS #11 session login state: logged out | logged in
2566 - the status of the PIN: no pin | valid pin | invalid pin | pin pad
2567 - the ID of the certificate object
2568 - the label of the certificate object
2569 - the subject distinguished name of the certificate
2574 ipsec auto --listall [--utc]
2579 ipsec listpubkeys [--utc]
2580 ipsec listcerts [--utc]
2581 ipsec listcacerts [--utc]
2582 ipsec listaacerts [--utc]
2583 ipsec listocspcerts [--utc]
2584 ipsec listacerts [--utc]
2585 ipsec listgroups [--utc]
2586 ipsec listcainfos [--utc]
2587 ipsec listcrls [--utc]
2588 ipsec listocsp [--utc]
2589 ipsec listcards [--utc]
2592 11. Firewall support functions
2593 --------------------------
2596 11.1 Environment variables in the updown script
2597 ------------------------------------------
2599 strongSwan makes the following environment variables available
2600 in the updown script indicated by the leftupdown option:
2602 +------------------------------------------------------------------+
2603 | Variable Example Comment |
2604 |------------------------------------------------------------------|
2605 | $PLUTO_PEER_ID carol@strongswan.org USER_FQDN (1) |
2606 |------------------------------------------------------------------|
2607 | $PLUTO_PEER_PROTOCOL 17 udp (2) |
2608 |------------------------------------------------------------------|
2609 | $PLUTO_PEER_PORT 68 bootpc (3) |
2610 |------------------------------------------------------------------|
2611 | $PLUTO_PEER_CA C=CH, O=ACME, CN=Sales CA (4) |
2612 |------------------------------------------------------------------|
2613 | $PLUTO_MY_ID @moon.strongswan.org FQDN (1) |
2614 |------------------------------------------------------------------|
2615 | $PLUTO_MY_PROTOCOL 17 udp (2) |
2616 |------------------------------------------------------------------|
2617 | $PLUTO_MY_PORT 67 bootps (3) |
2618 +------------------------------------------------------------------+
2620 (1) $PLUTO_PEER_ID/$PLUTO_MY_ID contain the IDs of the two ends
2621 of an established connection. In our examples these
2622 correspond to the strings defined by rightid and leftid,
2625 (2) $PLUTO_PEER_PROTOCOL/$PLUTO_MY_PROTOCOL contain the protocol
2626 defined by the rightprotoport and leftprotoport options,
2627 respectively. Both variables contain the same protocol value.
2628 The variables take on the value '0' if no protocol has been defined.
2630 (3) $PLUTO_PEER_PORT/$PLUTO_MY_PORT contain the ports defined by
2631 the rightprotoport and leftprotoport options, respectively.
2632 The variables take on the value '0' if no port has been defined.
2634 (4) $PLUTO_PEER_CA contains the distinguished name of the CA that
2635 issued the peer's certificate.
2638 11.2 Automatic insertion and deletion of iptables firewall rules
2639 -----------------------------------------------------------
2641 Starting with strongswan-2.7.0, the default _updown script automatically inserts
2642 and deletes dynamic iptables firewall rules upon the establishment or teardown,
2643 respectively, of an IPsec security association. This new feature is activated
2648 and can be used when the following prerequisites are fulfilled:
2650 - Linux 2.4.x kernel, KLIPS IPsec stack, and arbitrary iptables version.
2651 Filtering of tunneled traffic is based on ipsecN interfaces.
2653 - Linux 2.6.16 kernel or newer, native NETKEY IPsec stack, and
2654 iptables-1.3.5 or newer. Filtering of tunneled traffic is based on
2655 IPsec policy matching rules.
2657 If you define a local client subnet with a netmask larger than /32 behind
2658 the gateway then the automatically inserted FORWARD iptables rules will
2659 not allow to access the internal IP address of the host although it is
2660 part of the client subnet definition. If you want additional INPUT and
2661 OUTPUT iptables rules to be inserted, so that the host itself can be accessed
2662 then add the following line:
2666 The _updown script also features a logging facility which will register the
2667 creation (+) and the expiration (-) of each successfully established VPN
2668 connection in a special syslog file in the following concise and easily
2671 Jul 19 18:58:38 moon vpn:
2672 + @carol.strongswan.org 192.168.0.100 -- 192.168.0.1 == 10.1.0.0/16
2673 Jul 19 22:15:17 moon vpn:
2674 - @carol.strongswan.org 192.168.0.100 -- 192.168.0.1 == 10.1.0.0/16
2677 11.3 Sample Linux 2.6 updown script for iptables < 1.3.5
2678 ---------------------------------------------------
2680 If you are using a Linux 2.6 kernel older than 2.6.16 or an iptables version
2681 older than 1.3.5 then the IPsec policy matching rules will not be available.
2682 In order to make sure that only tunneled packets are accepted, a mark can be
2683 set on incoming ESP packets. This "ESP" mark will be retained on the
2684 decapsulated packet so that iptables rules inserted by the updown script can
2685 check on the presence of this mark. For this purpose the template located in
2687 programs/_updown_espmark
2689 can be used. Store a copy of _updown_espmark e.g. in /etc/ipsec.updown and load
2690 the script with the line
2692 leftupdown=/etc/updown.ipsec.
2694 In addition for the dynamic updown script to work the following static iptables rules
2697 iptables -t mangle -A INPUT -p 50 -j MARK --set-mark 50
2700 12. Authentication with raw RSA public keys
2701 ---------------------------------------
2703 FreeS/WAN, as it is available from www.freeswan.org does public key
2704 authentication with raw RSA public keys that are directly defined in
2707 rightrsasigkey=0sAq4c....
2709 When version 1.x of standard FreeS/WAN receives a certificate request (CR),
2710 it immediately drops the negotiation because it does not know how to answer
2711 the request. As a workaround strongSwan does not send a CR if the RSA
2712 key has been statically loaded using [right/left]rsasigkey. A problem
2713 remains with roadwarriors initiating a connection. Since strongSwan
2714 does not know the identity of the initiating peer in advance, it will always
2715 send a CR, causing the rupture of the IKE negotiation if the peer is a
2716 version 1.x FreeS/WAN host. To circumvent this problem the configuration
2717 parameter 'nocrsend' can be set in the config setup section of /etc/ipsec.conf:
2722 With this entry no certificate request is sent in any connection.
2723 The default setting is nocrsend=no.
2726 13. Authentication with OpenPGP certificates
2727 ----------------------------------------
2729 strongSwan also supports RSA based authentication using OpenPGP
2730 certificates and OpenPGP V3 fingerprints used as an KEY_ID identifier.
2733 13.1 OpenPGP certificates
2734 --------------------
2736 OpenPGP certificates containing RSA public keys can now directly be loaded
2737 in ASCII armored PGP format using the leftcert and rightcert parameters
2742 righcert=peerCert.asc
2744 leftcert=gatewayCert.asc
2746 The peer certificate must be stored locally (the default directory is
2747 /etc/ipsec.d/certs) since currently no trust can be established for
2748 PGP certificates received from a peer via the IKE protocol.
2751 13.2 OpenPGP private keys
2752 --------------------
2754 PGP private keys in unencrypted form can now directly be loaded in ASCII
2755 armored PGP format via an entry in /etc/ipsec.secrets:
2757 : RSA gatewayKey.asc
2759 Existing IDEA-encrypted RSA private keys can be unlocked with GnuPG and
2760 the IDEA extension (see http://www.gnupg.org/gph/en/pgp2x.html) using
2763 gpg --import gatewayCert.asc
2765 gpg --allow-secret-key-import --import gatewayKey.asc
2767 gpg --edit-key <gateway ID>
2768 > passwd #change to empty password
2771 gpg -a --export-secret-key <gateway ID> gatewayKey.asc
2774 13.3 Monitoring functions
2775 --------------------
2777 The command ipsec listcerts shows all loaded PGP certificates
2778 in the following format:
2780 Aug 28 09:51:55 2002, count: 1
2781 fingerprint: 0x1ccfca12d93467ffa9d5093d87a465dc
2782 pubkey: 1024 RSA Key ARHso6uKQ
2783 created: Aug 27 08:51:39 2002
2784 until: --- -- --:--:-- ---- ok (expires never)
2788 - the date the certificate was loaded either in local time or UTC (--utc)
2789 - the V3 fingerprint consisting of the 16 byte MD5 hash of the public key
2790 which is used as an ID of type KEY_ID
2791 - the modulus size of the RSA key in bits
2792 - a keyID consisting of 9 base64 symbols representing the public exponent
2793 and the most significant bits of the modulus
2794 - the creation date of the public key (extracted from the certificate)
2795 - the optional expiration date of the public key (extracted from the
2799 13.4 Suppression of certificate request messages
2800 -------------------------------------------
2802 PGPnet configured to work with OpenPGP certificates aborts the IKE
2803 negotiation when it receives a X.509 certificate. Therefore it is recommended
2804 (mandatory for roadwarrior connections) to set
2812 14. Additional Features
2816 14.1 Authentication and encryption algorithms
2817 ----------------------------------------
2819 strongSwan supports the following suite of encryption and authentication
2820 algorithms for both IKE and ESP payloads.
2822 +------------------------------------------------------------------+
2823 | IKE algorithms (negotiated in Phase 1 Main Mode) |
2824 +------------------------------------------------------------------+
2825 | Encryption algorithms: 3des, aes, serpent, twofish, blowfish |
2826 |------------------------------------------------------------------|
2827 | Hash algorithms: md5, sha, sha2 |
2828 |------------------------------------------------------------------|
2829 | DH groups: 1024, 1536, 2048, 3072, 4096, 6144, 8192 |
2830 +------------------------------------------------------------------+
2832 NOTE: For IKE the SHA-1 algorithm is denoted by "sha"
2834 The cryptographic IKE algorithms listed above are a fixed part of the
2835 strongSwan distribution. Particular algorithms can be added or removed
2836 in the "programs/pluto/alg" directory.
2838 +------------------------------------------------------------------+
2839 | ESP algorithms (negotiated in Phase 2 Quick Mode) |
2840 +------------------------------------------------------------------+
2841 | Encryption algorithms: 3des, aes, serpent, twofish, blowfish |
2842 |------------------------------------------------------------------|
2843 | Hash algorithms: md5, sha1, sha2 |
2844 |------------------------------------------------------------------|
2845 | PFS groups: 1024, 1536, 2048, 3072, 4096, 6144, 8192 |
2846 +------------------------------------------------------------------+
2848 The cryptographic ESP algorithms listed above are a fixed part of the
2849 strongSwan distribution. If your Linux 2.4 or 2.6 kernel includes the
2850 CryptoAPI then additional ESP algorithms can be added or deleted as
2853 The IKE and ESP cryptographic algorithms to be proposed to the peer
2854 as an initiator can be specified on a per connection basis in the form
2858 ike=aes128-sha-modp1536,3des-sha-modp1536
2859 esp=aes128-sha1,3des-sha1
2862 or if you are more paranoid
2866 ike=aes256-sha2_512-modp2048
2870 If the the "ike" and "esp" configuration parameters are missing in
2871 ipsec.conf, then the default settings
2873 ike=3des-md5-modp1536,3des-sha-modp1536,\
2874 3des-md5-modp1024,3des-sha-modp1024
2875 esp=3des-md5,3des-sha1
2877 arre implicitly assumed. The 3DES encryption algorithm and the MD5 and
2878 SHA-1 hash algorithms are hardcoded into strongSwan and cannot be removed.
2880 If Perfect Forward Secrecy (PFS is desired), then a PFS group can be
2881 optionally specified:
2886 pfsgroup=modp2048,modp1536
2889 If the "pfs" parameter is missing then "pfs=yes" is assumed by default.
2890 This means that PFS must be disabled explicitly by setting "pfs=no".
2892 If the "pfsgroup" parameter is missing then the default is
2894 pfsgroup=<Phase1 DH group>
2896 The "ike" and "esp" parameters are used to formulate one or several
2897 transform proposals to the peer if the strongSwan VPN host is the initiator.
2898 Attention! As a responder the first proposal from the peer is accepted that
2899 is supported the by one of the registered algorithms listed by the command
2903 If the responder wants to restrict the allowed cipher suites the '!' flag
2904 can be used to do so. The configuration
2906 conn normal_but_strict
2908 ike=aes128-sha-modp1536,3des-sha-modp1536!
2909 esp=aes128-sha1,3des-sha1!
2912 will only permit the listed algorithms defined above but no other methods
2913 even if they might be supported by the responder.
2919 Currently please refer to README.NAT-Traversal document in the strongSwan
2923 14.3 Dead peer detection
2924 --------------------
2926 strongSwan implements the RFC 3706 Dead Peer Detection (DPD) keep-alive
2927 scheme. If an established IPsec SA has been idle (i.e. without any traffic)
2928 for N seconds (dpddelay=N) then strongSwan side sends a "hello" message
2929 (R_U_THERE) and the peer replies with an acknowledge message (R_U_THERE_ACK).
2930 If no response is received, the R_U_THERE messages are repeated until a DPD
2931 timeout of M seconds (dpdtimeout=M) has elapsed. If still no traffic or
2932 R_U_THERE_ACK packets were received, the peer is declared to be dead and all
2933 SAs belonging to a common Phase 1 SA are deleted.
2935 DPD support is tuneable on a per connection basis by using the dpdaction,
2936 dpddelay and dpdtimeout directives:
2941 leftsubnet=10.1.0.0/16
2946 rightsubnet=10.2.0.0/16
2948 leftsubnet=10.1.0.0/16
2953 In the first example dpdaction=clear activates the DPD mechanism under the
2954 condition that the peer supports RFC 3706. The values dpddelay=30s and
2955 dpdtimeout=120s are assumed by default in the absence of these parameters, so
2956 that during idle periods an R_U_THERE packet is sent every 30 seconds. If no
2957 traffic or a no R_U_THERE_ACK packet is received from the peer within a
2958 120 second time span, the peer will be declared dead and all SAs and associated
2959 eroutes will be cleared.
2961 In the second example R_U_THERE packets are sent every 60 seconds and the
2962 parameter setting dpdaction=hold will put the eroute of the ruptured connection
2963 into a %trap state, so that when new outgoing traffic will occur, the
2964 correspondig connection will be automatically renegotiated as soon as the
2967 It is recommended to use dpdaction=hold for statically defined connections and
2968 dpdaction=clear for dynamic roadwarrior connections. The default value is
2969 dpdaction=none, which disables DPD.
2972 14.4 IKE Mode Config
2975 The IKE Mode Config protocol <draft-ietf-ipsec-isakmp-mode-cfg-04.txt> allows
2976 the dynamic assignment of virtual IP addresses and optional DNS and WINS server
2977 information to IPsec clients. Currently only "Mode Config Pull Mode" is
2978 implemented where the client actively sends a Mode Config request to the server
2979 in order to obtain a virtual IP.
2981 Client side configuration (carol):
2985 rightsubnet=10.1.0.0/16
2986 rightid=@moon.strongswan.org
2988 leftsourceip=%modeconfig
2989 leftcert=carolCert.pem
2990 leftid=carol@strongswan.org
2993 Server side configuration (moon):
2997 rightid=carol@strongswan.org
2998 rightsourceip=10.3.0.1
3000 leftsubnet=10.1.0.0/16
3001 leftcert=moonCert.pem
3002 leftid=@moon.strongswan.org
3005 The wildcard %modeconfig or %modecfg used in the leftsourceip parameter of the
3006 client will trigger a Mode Config request. Currently the server will return
3007 the virtual IP address defined by the rightsourceip parameter. In the future
3008 an LDAP-based lookup mechanism will be supported.
3011 15. Copyright statement and acknowledgements
3012 ----------------------------------------
3015 FreeS/WAN version base system:
3017 Copyright (c) 1999-2004
3018 Henry Spencer, Richard Guy Briggs,
3019 D. Hugh Redelmeier, Sandy Harris, Claudia Schmeing,
3020 Michael Richardson, Angelos D. Keromytis, John Ioannidis,
3022 NAT-Traversal, ipsec starter, Delete SA and Notification messages:
3024 Copyright (c) 2002-2003, Mathieu Lafon
3026 Additional cryptoalgorithms (AES, etc):
3028 Copyright (c) 2002-2003, JuanJo Ciarlante
3030 Dead Peer Detection:
3032 Copyright (c) 2002-2004
3033 Ken Bantoft, JuanJo Ciarlante, Philip Craig,
3034 Pawel Krawczyk, Srinvasan Venkataraman
3036 Porting to Linux 2.6 kernel:
3038 Copyright (c) 2003, Herbert Xu
3040 Dynamic CRL fetching:
3042 Copyright (c) 2002, Stephane Laroche
3044 IKE Mode Config protocol:
3046 Copyright (c) 2001-2002, Colubris Networks
3048 Virtual IP and source routing:
3050 Copyright (c) 2003, Tuomo Soini
3052 Port and protocol selectors for outbound traffic:
3054 Copyright (c) 2002, Stephen J. Bevan
3056 PGPnet-RSA parts of patch:
3058 Copyright (c) 2000, Kai Martius
3060 X.509, OCSP and smartcard functionality:
3062 Copyright (c) 2000, Andreas Hess, Patric Lichtsteiner, Roger Wegmann
3063 Copyright (c) 2001, Marco Bertossa, Andreas Schleiss
3064 Copyright (c) 2002, Uli Galizzi, Ariane Seiler, Mario Strasser
3065 Copyright (c) 2002, Martin Berner, Lukas Suter
3066 Copyright (c) 2003, Christoph Gysin, Simon Zwahlen
3067 Copyright (c) 2004, David Buechi, Michael Meier
3068 Copyright (c) 2000-2005, Andreas Steffen
3070 Zurich University of Applied Sciences in Winterthur, Switzerland
3074 Copyright (c) 2005, Jan Hutter, Martin Willi
3075 Copyright (c) 2005-2006, Andreas Steffen
3077 University of Applied Sciences in Rapperswil, Switzerland
3079 This program is free software; you can redistribute it and/or modify
3080 it under the terms of the GNU General Public License as published by
3081 the Free Software Foundation; either version 2 of the License, or
3082 (at your option) any later version. See http://www.fsf.org/copyleft/gpl.txt.
3084 This program is distributed in the hope that it will be useful, but
3085 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
3086 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
3088 -----------------------------------------------------------------------------
3090 This file is RCSID $Id: README,v 1.33 2006/04/24 21:27:49 as Exp $