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
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
72 14.4 IKE Mode Config Pull Mode
73 14.5 IKE Mode Config Push Mode
74 14.6 XAUTH - Extended Authentication (NEW)
75 15. Copyright statement and acknowledgements
81 strongSwan is an OpenSource IPsec solution for the Linux operating system
82 and currently supports the following features:
84 * runs both on Linux 2.4 (KLIPS) and Linux 2.6 (native IPsec) kernels.
86 * strong 3DES, AES, Serpent, Twofish, or Blowfish encryption.
88 * Authentication based on X.509 certificates or preshared secrets.
90 * IPsec policies based on wildcards or intermediate CAs.
92 * Powerful and flexible IPsec policies based on group attributes.
94 * Retrieval of Certificate Revocation Lists (CRLs) via HTTP or LDAP.
96 * Local caching of fetched CRLs
98 * Full support of the Online Certificate Status Protocol (OCSP, RFC 2560).
100 * CA management functions including OCSP and CRL URIs and default LDAP server.
102 * Optional storage of RSA private keys on smartcards or USB crypto tokens
104 * Standardized PKCS#11 interface with optional proxy functions serving
105 external applications (disc encryption, etc.).
107 * NAT-Traversal (RFC 3947)
109 * Support of Virtual IPs via static configuration and IKE Mode Config
111 * XAUTH client and server functionality in conjunction with either PSK
112 or RSA IKE Main Mode authentication.
114 * Support of Delete SA and informational Notification messages.
116 * Dead Peer Detection (DPD, RFC 3706)
118 Compatibility has successfully been tested with peers running the following
121 FreeS/WAN, Openswan, SafeNet/SoftRemote, NCP Secure Entry Client,
122 SonicWALL Global VPN Client, The GreenBow, Microsoft Windows 2000/XP, etc.
124 Furthermore, interoperability with the following VPN gateways
125 has been demonstrated during the IPsec 2001 Conference in Paris:
127 Cisco IOS Routers, Cisco PIX firewall, Cisco VPN3000,
128 Nortel Contivity VPN Switch, NetScreen (FreeS/WAN as responder only),
129 OpenBSD with isakmpd, Netasq, Netcelo, and 6WIND.
131 Potentially any IPsec implementation with X.509 certificate support can
132 be made to cooperate with strongSwan. The latest addition has been the successful
133 interoperability with the Check Point VPN-1 NG gateway.
139 In the following examples we assume for reasons of clarity that left designates
140 the local host and that right is the remote host. Certificates for users, hosts
141 and gateways are issued by a ficticious strongSwan CA. How to generate private keys
142 and certificates using OpenSSL will be explained in section 3. The CA certificate
143 "strongswanCert.pem" must be present on all VPN end points in order to be able to
144 authenticate the peers.
147 2.1 Site-to-site case
150 In this scenario two security gateways moon and sun will connect the
151 two subnets moon-net and sun-net with each other through a VPN tunnel
152 set up between the two gateways:
154 10.1.0.0/16 -- | 192.168.0.1 | === | 192.168.0.2 | -- 10.2.0.0/16
155 moon-net moon sun sun-net
157 Configuration on gateway moon:
159 /etc/ipsec.d/cacerts/strongswanCert.pem
161 /etc/ipsec.d/certs/moonCert.pem
165 : RSA moonKey.pem "<optional passphrase>"
171 leftsubnet=10.1.0.0/16
172 leftcert=moonCert.pem
174 rightsubnet=10.2.0.0/16
175 rightid="C=CH, O=Linux strongSwan, CN=sun.strongswan.org"
178 Configuration on gateway sun:
180 /etc/ipsec.d/cacerts/strongswanCert.pem
182 /etc/ipsec.d/certs/sunCert.pem
186 : RSA sunKey.pem "<optional passphrase>"
192 leftsubnet=10.2.0.0/16
195 rightsubnet=10.1.0.0/16
196 rightid="C=CH, O=Linux strongSwan, CN=moon.strongswan.org"
200 2.2 Host-to-host case
203 This is a setup between two single hosts which don't have a subnet behind
204 them. Although IPsec transport mode would be sufficient for host-to-host
205 connections we will use the default IPsec tunnel mode.
207 | 192.168.0.1 | === | 192.168.0.2 |
210 Configuration on host moon:
212 /etc/ipsec.d/cacerts/strongswanCert.pem
214 /etc/ipsec.d/certs/moonCert.pem
218 : RSA moonKey.pem "<optional passphrase>"
224 leftcert=moonCert.pem
226 rightid="C=CH, O=Linux strongSwan, CN=sun.strongswan.org"
229 Configuration on host sun:
231 /etc/ipsec.d/cacerts/strongswanCert.pem
233 /etc/ipsec.d/certs/sunCert.pem
237 : RSA sunKey.pem "<optional passphrase>"
245 rightid="C=CH, O=Linux strongSwan, CN=moon.strongswan.org"
252 In a site-to-site setup a system administrator logged into the local gateway
253 often would like to access the peer gateway or a server in the subnet behind
254 the peer gateway over a secure IPsec tunnel.Since IP packets leaving a gateway
255 via the outer network interface carry the IP address of this NIC, four IPsec
256 Security Associations (SAs) must be set up to achieve full connectivity. The
257 example below shows how this can be done without much additional typing work ,
258 using the "also" macro which includes connection definitions defined farther
259 down in the ipsec.conf file.
261 10.1.0.0/16 -- | 192.168.0.1 | === | 192.168.0.2 | -- 10.2.0.0/16
262 moon-net moon sun sun-net
264 Configuration on gateway moon:
266 /etc/ipsec.d/cacerts/strongswanCert.pem
268 /etc/ipsec.d/certs/moonCert.pem
272 : RSA moonKey.pem "<optional passphrase>"
277 leftsubnet=10.1.0.0/16
278 rightsubnet=10.2.0.0/16
282 leftsubnet=10.1.0.0/16
286 rightsubnet=10.2.0.0/16
291 leftcert=moonCert.pem
293 rightid="C=CH, O=Linux strongSwan, CN=sun.strongswan.org"
296 Configuration on gateway sun:
298 /etc/ipsec.d/cacerts/strongswanCert.pem
300 /etc/ipsec.d/certs/sunCert.pem
304 : RSA sunKey.pem "<optional passphrase>"
309 leftsubnet=10.2.0.0/16
310 rightsubnet=10.1.0.0/16
314 leftsubnet=10.2.0.0/16
318 rightsubnet=10.1.0.0/16
325 rightid="C=CH, O=Linux strongSwan, CN=moon.strongswan.org"
329 2.4 The four tunnel case the elegant way with source routing
330 --------------------------------------------------------
332 As you certainly agree, the full four tunnel case described in the previous
333 section becomes quite complex. If we could force the source address of the
334 IP packets leaving the gateway through the outer interface to take on the
335 IP address of the inner interface then we could use the single subnet-to-subnet
336 tunnel from section 2.1. Such a setup becomes possible if we use the
337 source routing capabilites of the ip route command that is already used
338 by strongSwan's updown scripts.
340 10.1.0.0/16 -- | 192.168.0.1 | === | 192.168.0.2 | -- 10.2.0.0/16
341 moon-net moon sun sun-net
343 If we assume that the inner IP address of gateway moon is 10.1.0.1
344 and the inner IP address of gateway sun is 10.2.0.1 then the
345 insertion of the parameter
347 leftsourceip=10.1.0.1
349 in the connection definition of moon and
351 leftsourceip=10.2.0.1
353 on sun, respectively, will install source routing on both gateways.
354 As a result the command
358 executed on moon will leave the gateway with a source address of
359 10.1.0.1 and will therefore take the net-net IPsec tunnel.
361 Configuration on gateway moon:
363 /etc/ipsec.d/cacerts/strongswanCert.pem
365 /etc/ipsec.d/certs/moonCert.pem
369 : RSA moonKey.pem "<optional passphrase>"
375 leftsourceip=10.1.0.1
376 leftsubnet=10.1.0.0/16
377 leftcert=moonCert.pem
379 rightsubnet=10.2.0.0/16
380 rightid="C=CH, O=Linux strongSwan, CN=sun.strongswan.org"
383 Configuration on gateway sun:
385 /etc/ipsec.d/cacerts/strongswanCert.pem
387 /etc/ipsec.d/certs/sunCert.pem
391 : RSA sunKey.pem "<optional passphrase>"
397 leftsubnet=10.2.0.0/16
398 leftsourceip=10.2.0.1
401 rightsubnet=10.1.0.0/16
402 rightid="C=CH, O=Linux strongSwan, CN=moon.strongswan.org"
409 This is a very common case where a strongSwan gateway serves an arbitrary number
410 of remote VPN clients usually having dynamic IP addresses.
412 10.1.0.0/16 -- | 192.168.0.1 | === | x.x.x.x |
415 Configuration on gateway moon:
417 /etc/ipsec.d/cacerts/strongswanCert.pem
419 /etc/ipsec.d/certs/moonCert.pem
423 : RSA moonKey.pem "<optional passphrase>"
429 leftsubnet=10.1.0.0/16
430 leftcert=moonCert.pem
434 Configuration on roadwarrior carol:
436 /etc/ipsec.d/cacerts/strongswanCert.pem
438 /etc/ipsec.d/certs/carolCert.pem
442 : RSA carolKey.pem "<optional passphrase>"
448 leftcert=carolCert.pem
450 rightsubnet=10.1.0.0/16
451 rightid="C=CH, O=Linux strongSwan, CN=moon.strongswan.org"
455 2.6 Roadwarrior case with virtual IP
456 --------------------------------
458 Roadwarriors usually have dynamic IP addresses assigned by the ISP they are
459 currently attached to. In order to simplify the routing from moon-net back
460 to the remote access client carol it would be desirable if the roadwarrior had
461 an inner IP address chosen from a pre-assigned pool.
463 10.1.0.0/16 -- | 192.168.0.1 | === | x.x.x.x | -- 10.3.0.1
464 moon-net moon carol virtual IP
466 This virtual IP address can be assigned to a strongSwan roadwarrior by adding
469 leftsourceip=10.3.0.1
471 to the roadwarrior's ipsec.conf. Of course the virtual IP of each roadwarrior
472 must be distinct. In our example it is chosen from the address pool
474 rightsubnetwithin=10.3.0.0/16
476 which can be added to the gateway's ipsec.conf so that a single connection
477 definition can handle multiple roadwarriors.
479 Configuration on gateway moon:
481 /etc/ipsec.d/cacerts/strongswanCert.pem
483 /etc/ipsec.d/certs/moonCert.pem
487 : RSA moonKey.pem "<optional passphrase>"
493 leftsubnet=10.1.0.0/16
494 leftcert=moonCert.pem
496 rightsubnetwithin=10.3.0.0/16
499 Configuration on roadwarrior carol:
501 /etc/ipsec.d/cacerts/strongswanCert.pem
503 /etc/ipsec.d/certs/carolCert.pem
507 : RSA carolKey.pem "<optional passphrase>"
513 leftsourceip=10.3.0.1
514 leftcert=carolCert.pem
516 rightsubnet=10.1.0.0/16
517 rightid="C=CH, O=Linux strongSwan, CN=moon.strongswan.org"
521 3. Generating certificates and CRLs with OpenSSL
522 ---------------------------------------------
524 This section is not a full-blown tutorial on how to use OpenSSL. It just lists
525 a few points that are relevant if you want to generate your own certificates
526 and CRLs for use with strongSwan.
529 3.1 Generating a CA certificate
530 ---------------------------
532 The OpenSSL statement
534 openssl req -x509 -days 1460 -newkey rsa:2048 \
535 -keyout strongswanKey.pem -out strongswanCert.pem
537 creates a 2048 bit RSA private key strongswanKey.pem and a self-signed CA
538 certificate strongswanCert.pem with a validity of 4 years (1460 days).
540 openssl x509 -in cert.pem -noout -text
542 lists the properties of a X.509 certificate cert.pem. It allows you to verify
543 whether the configuration defaults in openssl.cnf have been inserted correctly.
545 If you prefer the CA certificate to be in binary DER format then the following
546 command achieves this transformation:
548 openssl x509 -in strongswanCert.pem -outform DER -out strongswanCert.der
550 The directory /etc/ipsec.d/cacerts contains all required CA certificates either
551 in binary DER or in base64 PEM format. Irrespective of the file suffix, Pluto
552 "automagically" determines the correct format.
555 3.2 Generating a host or user certificate
556 -------------------------------------
558 The OpenSSL statement
560 openssl req -newkey rsa:1024 -keyout hostKey.pem \
563 generates a 1024 bit RSA private key hostKey.pem and a certificate request
564 hostReq.pem which has to be signed by the CA.
566 If you want to add a subjectAltName field to the host certificate you must edit
567 the OpenSSL configuration file openssl.cnf and add the following line in the
568 [ usr_cert ] section:
570 subjectAltName=DNS:moon.strongswan.org
572 if you want to identify the host by its Fully Qualified Domain Name (FQDN ), or
574 subjectAltName=IP:192.168.0.1
576 if you want the ID to be of type IPV4_ADDR. Of course you could include both
579 subjectAltName=DNS:moon.strongswan.org,IP:192.168.0.1
581 but the use of an IP address for the identification of a host should be
584 For user certificates the appropriate ID type is USER_FQDN which can be
587 subjectAltName=email:carol@strongswan.org
589 or if the user's e-mail address is part of the subject's distinguished name
591 subjectAltName=email:copy
593 Now the certificate request can be signed by the CA with the command
595 openssl ca -in hostReq.pem -days 730 -out hostCert.pem -notext
597 If you omit the -days option then the default_days value (365 days) specified
598 in openssl.cnf is used. The -notext option avoids that a human readable
599 listing of the certificate is prepended to the base64 encoded certificate
602 If you want to use the dynamic CRL fetching feature described in section 4.7
603 then you may include one or several crlDistributionPoints in your end
604 certificates. This can be done in the [ usr_cert ] section of the openssl.cnf
607 crlDistributionPoints= @crl_dp
611 URI.1="http://crl.strongswan.org/strongswan.crl"
612 URI.2="ldap://ldap.strongswan.org/cn=strongSwan Root CA, o=Linux strongSwan
613 , c=CH?certificateRevocationList"
615 If you have only a single http distribution point then the short form
617 crlDistributionPoints="URI:http://crl.strongswan.org/strongswan.crl"
619 also works. Due to a known bug in OpenSSL this notation fails with ldap URIs.
621 Usually a Windows-based VPN client needs its private key, its host or
622 user certificate, and the CA certificate. The most convenient way to load
623 this information is to put everything into a PKCS#12 file:
625 openssl pkcs12 -export -inkey carolKey.pem \
626 -in carolCert.pem -name "carol" \
627 -certfile strongswanCert.pem -caname "strongSwan Root CA" \
634 An empty CRL that is signed by the CA can be generated with the command
636 openssl ca -gencrl -crldays 15 -out crl.pem
638 If you omit the -crldays option then the default_crl_days value (30 days)
639 specified in openssl.cnf is used.
641 If you prefer the CRL to be in binary DER format then this conversion
644 openssl crl -in crl.pem -outform DER -out cert.crl
646 The directory /etc/ipsec.d/crls contains all CRLs either in binary DER
647 or in base64 PEM format. Irrespective of the file suffix, Pluto
648 "automagically" determines the correct format.
651 3.4 Revoking a certificate
652 ----------------------
654 A specific host certificate stored in the file host.pem is revoked with the
657 openssl ca -revoke host.pem
659 Next the CRL file must be updated
661 openssl ca -gencrl -crldays 60 -out crl.pem
663 The content of the CRL file can be listed with the command
665 openssl crl -in crl.pem -noout -text
667 in the case of a base64 CRL, or alternatively for a CRL in DER format
669 openssl crl -inform DER -in cert.crl -noout -text
673 4. Configuring the connections - ipsec.conf
674 ----------------------------------------
676 4.1 Configuring my side
679 Usually the local side is the same for all connections. Therefore it makes
680 sense to put the definitions characterizing the strongSwan security gateway into
681 the conn %default section of the configuration file /etc/ipsec.conf. If we
682 assume throughout this document that the strongSwan security gateway is left and
683 the peer is right then we can write
686 # my side is left - the freeswan security gateway
688 leftcert=moonCert.pem
689 # load connection definitions automatically
692 The X.509 certificate by which the strongSwan security gateway will authenticate
693 itself by sending it in binary form to its peers as part of the Internet Key
694 Exchange (IKE) is specified in the line
696 leftcert=moonCert.pem
698 The certificate can either be stored in base64 PEM-format or in the binary
699 DER-format. Irrespective of the file suffix, Pluto "automagically" determines
700 the correct format. Therefore
702 leftcert=moonCert.der
706 leftcert=moonCert.cer
708 would also be valid alternatives.
710 When using relative pathnames as in the examples above, the certificate files
711 must be stored in in the directory /etc/ipsec.d/certs. In order to distinguish
712 strongSwan's own certificates from locally stored trusted peer certificates
713 (see section 5.5 for details), they could also be stored in a subdirectory
714 below /etc/ipsec.d/certs as e.g. in
716 leftcert=mycerts/moonCert.pem
718 Absolute pathnames are also possible as in
720 leftcert=/usr/ssl/certs/moonCert.pem
722 As an ID for the VPN gateway we recommend the use of a Fully Qualified Domain
723 Name (FQDN) of the form
727 leftid=@moon.strongswan.org
729 Important: When an FQDN identifier is used it must be explicitly included as a
730 so called subjectAltName of type dnsName (DNS:) in the certificate indicated
731 by leftcert. For details on how to generate certificates with subjectAltNames,
732 please refer to section 7.2.
734 If you don't want to mess with subjectAltNames, you can use the certificate's
735 Distinguished Name (DN) instead, which is an identifier of type DER_ASN1_DN
736 and which can be written e.g. in the LDAP-type format
740 leftid="C=CH, O=Linux strongSwan, CN=moon.strongswan.org"
742 Since the subject's DN is part of the certificate, the leftid does not have to
743 be declared explicitly. Thus the entry
748 automatically assumes the subject DN of leftcert to be the host ID.
751 4.2 Multiple certificates
752 ---------------------
754 strongSwan supports multiple local host certificates and corresponding
759 rightid=@peer1.domain1
761 # leftid is DN of myCert1
765 rightid=@peer2.domain2
767 # leftid is DN of myCert2
769 When peer1 initiates a connection then strongSwan will send myCert1 and will
770 sign with myKey1 defined in /etc/ipsec.secrets (see section 6.2) whereas
771 myCert2 and myKey2 will be used in a connection setup started from peer2.
774 4.3 Configuring the peer side using CA certificates
775 -----------------------------------------------
777 Now we can proceed to define our connections. In many applications we might
778 have dozens of mostly Windows-based road warriors connecting to a central
779 strongSwan security gateway. The following most simple statement:
784 defines the general roadwarrior case. The line right=%any literally means that
785 any IPSec peer is accepted, regardless of its current IP source address and its
786 ID, as long as the peer presents a valid X.509 certificate signed by a CA the
787 strongSwan security gateway puts explicit trust in. Additionally the signature
788 during IKE main mode gives proof that the peer is in possession of the private
789 RSA key matching the public key contained in the transmitted certificate.
791 The ID by which a peer is identifying itself during IKE main mode can by any of
792 the ID types IPV4_ADDR, FQDN, USER_FQDN or DER_ASN1_DN. If one of the first
793 three ID types is used, then the accompanying X.509 certificate of the peer
794 must contain a matching subjectAltName field of the type ipAddress (IP:),
795 dnsName (DNS:) or rfc822Name (email:), respectively. With the fourth type
796 DER_ASN1_DN the identifier must completely match the subject field of the
797 peer's certificate. One of the two possible representations of a
798 Distinguished Name (DN) is the LDAP-type format
800 rightid="C=CH, O=Linux strongSwan, CN=sun.strongswan.org"
802 Additional whitespace can be added everywhere as desired since it will be
803 automatically eliminated by the X.509 parser. An exception is the single
804 whitespace between individual words , like e.g. in Linux strongSwan, which is
805 preserved by the parser.
807 The Relative Distinguished Names (RDNs) can alternatively be separated by a
808 slash '/' instead of a comma ','
810 rightid="/C=CH/O=Linux strongSwan/CN=sun.strongswan.org"
812 This is the representation extracted from the certificate by the OpenSSL
815 openssl x509 -in sunCert.pem -noout -subject
817 The following RDNs are supported by strongSwan
819 +---------------------------------------------------+
820 | DC Domain Component |
821 |---------------------------------------------------|
823 |---------------------------------------------------|
824 | ST State or province |
825 |---------------------------------------------------|
826 | L Locality or town |
827 |---------------------------------------------------|
829 |---------------------------------------------------|
830 | OU Organisational Unit |
831 |---------------------------------------------------|
833 |---------------------------------------------------|
834 | ND NameDistinguisher, used with CN |
835 |---------------------------------------------------|
837 |---------------------------------------------------|
839 |---------------------------------------------------|
841 |---------------------------------------------------|
843 |---------------------------------------------------|
845 |---------------------------------------------------|
847 |---------------------------------------------------|
849 |---------------------------------------------------|
850 | emailAddress E-mail |
851 |---------------------------------------------------|
853 |---------------------------------------------------|
854 | serialNumber Serial number |
855 |---------------------------------------------------|
857 |---------------------------------------------------|
858 | ID X.500 Unique Identifier |
859 |---------------------------------------------------|
861 |---------------------------------------------------|
862 | TCGID [Siemens] Trust Center Global ID |
863 |---------------------------------------------------|
864 | unstructuredName Unstructured Name |
865 |---------------------------------------------------|
866 | UN Unstructured Name |
867 |---------------------------------------------------|
868 | employeeNumber Employee Number |
869 |---------------------------------------------------|
870 | EN Employee Number |
871 +---------------------------------------------------+
873 With the roadwarrior connection definition listed above, an IPsec SA for
874 the strongSwan security gateway moon.strongswan.org itself can be established.
875 If any roadwarrior should be able to reach e.g. the two subnets 10.1.0.0/24
876 and 10.1.3.0/24 behind the security gateway then the following connection
877 definitions will make this possible
881 leftsubnet=10.1.0.0/24
885 leftsubnet=10.1.3.0/24
887 If not all peers in possession of a X.509 certificate signed by a specific
888 certificate authority shall be given access to the Linux security gateway,
889 then either a subset of them can be barred by listing the serial numbers of
890 their certificates in a certificate revocation list (CRL) as specified in
891 section 5.2 or as an alternative, access can be controlled by explicitly
892 putting a roadwarrior entry for each eligible peer into ipsec.conf:
896 rightid=@sun.strongswan.org
900 rightid=carol@strongswan.org
904 rightid="C=CH, O=Linux strongSwan, CN=dave@strongswan.org"
906 When the IP address of a peer is known to be stable, it can be specified as
907 well. This entry is mandatory when the strongSwan host wants to act as the
908 initiator of an IPSec connection.
912 rightid=@sun.strongswan.org
916 rightid=carol@strongswan.org
920 rightid="C=CH, O=Linux strongSwan, CN=dave@strongswan.org"
925 In the last example the ID types FQDN, USER_FQDN, DER_ASN1_DN and IPV4_ADDR,
926 respectively, were used. Of course all connection definitions presented so far
927 have included the lines in the conn %defaults section, comprising among other
928 a left and leftcert entry.
931 4.4 Handling Virtual IPs and wildcard subnets
932 -----------------------------------------
934 Often roadwarriors are behind NAT-boxes with IPsec passthrough, which causes
935 the inner IP source address of an IPsec tunnel to be different from the
936 outer IP source address usually assigned dynamically by the ISP.
937 Whereas the varying outer IP address can be handled by the right=%any
938 construct, the inner IP address or subnet must always be declared in a
939 connection definition. Therefore for the three roadwarriors rw1 to rw3
940 connecting to a strongSwan security gateway the following entries are
941 required in /etc/ipsec.conf:
945 righsubnet=10.4.0.5/32
949 rightsubnet=10.4.0.47/32
953 rightsubnet=10.4.0.128/28
955 With the wildcard parameter rightsubnetwithin these three entries can be
956 reduced to the single connection definition
960 rightsubnetwithin=10.4.0.0/24
962 Any host will be accepted (of course after successful authentication based on
963 the peer's X.509 certificate only) if it declares a client subnet lying totally
964 within the brackets defined by the wildcard subnet definition (in our example
965 10.4.0.0/24). For each roadwarrior a connection instance tailored to the
966 subnet of the particular client will be created,based on the generic
967 rightsubnetwithin template.
969 This strongSwan feature can also be helpful with VPN clients getting a
970 dynamically assigned inner IP from a DHCP server located on the NAT router box.
973 4.5 Protocol and Port Selectors
974 ---------------------------
976 strongSwan offer the possibility to restrict the protocol and optionally the
977 ports in an IPsec SA using the rightprotoport and leftprotoport parameters.
985 leftid=@moon.strongswan.org
992 leftid=@moon.strongswan.org
995 conn l2tp # with port wildcard for Mac OS X Panther interoperability
997 rightprotoport=17/%any
999 leftid=@moon.strongswan.org
1000 leftprotoport=17/1701
1004 rightprotoport=udp/bootpc
1006 leftid=@moon.strongswan.org
1007 leftsubnet=0.0.0.0/0 #allows DHCP discovery broadcast
1008 leftprotoport=udp/bootps
1014 Protocols and ports can be designated either by their numerical values
1015 or by their acronyms defined in /etc/services.
1019 shows the following connection definitions:
1021 "icmp": 192.168.0.1[@moon.strongswan.org]:1/0...%any:1/0
1022 "http": 192.168.0.1[@moon.strongswan.org]:6/80...%any:6/0
1023 "l2tp": 192.168.0.1[@moon.strongswan.org]:17/1701...%any:17/%any
1024 "dhcp": 0.0.0.0/0===192.168.0.1[@moon.strongswan.org]:17/67...%any:17/68
1026 Based on the protocol and port selectors appropriate eroutes will be set
1027 up, so that only the specified payload types will pass through the IPsec
1031 4.6 IPsec policies based on wildcards
1032 ---------------------------------
1034 In large VPN-based remote access networks there is often a requirement that
1035 access to the various parts of an internal network must be granted selectively,
1036 e.g. depending on the group membership of the remote access user. strongSwan
1037 makes this possible by applying wildcard filtering on the VPN user's
1038 distinguished name (ID_DER_ASN1_DN).
1040 Let's make a practical example:
1042 An organization has a sales department (OU=Sales) and a research group
1043 (OU=Research). In the company intranet there are separate subnets for Sales
1044 (10.0.0.0/24) and Research (10.0.1.0/24) but both groups share a common web
1045 server (10.0.2.100). The VPN clients use Virtual IP addresses that are either
1046 assigned statically or via DHCP-over-IPsec. The sales and research departments
1047 use IP addresses from separate DHCP address pools (10.1.0.0/24) and (10.1.1.0/24),
1048 respectively. An X.509 certificate is issued to each employee, containing in its
1049 subject distinguished name the country (C=CH), the company (O=ACME),
1050 the group membership(OU=Sales or OU=Research) and the common name (e.g.
1053 The IPsec policy defined above can now be enforced with the following three
1054 IPsec security associations:
1058 rightid="C=CH, O=ACME, OU=Sales, CN=*"
1059 rightsubnetwithin=10.1.0.0/24 # Sales DHCP range
1060 leftsubnet=10.0.0.0/24 # Sales subnet
1064 rightid="C=CH, O=ACME, OU=Research, CN=*"
1065 rightsubnetwithin=10.1.1.0/24 # Research DHCP range
1066 leftsubnet=10.0.1.0/24 # Research subnet
1070 rightid="C=CH, O=ACME, OU=*, CN=*"
1071 rightsubnetwithin=10.1.0.0/23 # Remote access DHCP range
1072 leftsubnet=10.0.2.100/32 # Web server
1073 rightprotoport=tcp # TCP protocol only
1074 leftprotoport=tcp/http # TCP port 80 only
1076 Of course group specific tunneling could be implemented on the
1077 basis of the Virtual IP range specified by the rightsubnetwithin
1078 parameter alone, but the wildcard matching mechanism guarantees that
1079 only authorized user can access the corresponding subnets.
1081 The '*' character is used as a wildcard in relative distinguished names (RDNs).
1082 In order to match a wildcard template, the ID_DER_ASN1_DN of a peer must contain
1083 the same number of RDNs (selected from the list in section 4.3) appearing in the
1084 exact order defined by the template.
1086 "C=CH, O=ACME, OU=Research, OU=Special Effects, CN=Bart Simpson"
1088 matches the templates
1090 "C=CH, O=ACME, OU=Research, OU=*, CN=*"
1092 "C=CH, O=ACME, OU=*, OU=Special Effects, CN=*"
1094 "C=CH, O=ACME, OU=*, OU=*, CN=*"
1096 but not the template
1098 "C=CH, O=ACME, OU=*, CN=*"
1100 which doesn't have the same number of RDNs.
1103 4.7 IPsec policies based on CA certificates
1104 ---------------------------------------
1106 As an alternative to the wildcard based IPsec policies described in section 4.6,
1107 access to specific client host and subnets can abe controlled on the basis of
1108 the CA that issued the peer certificate
1113 rightca="C=CH, O=ACME, OU=Sales, CN=Sales CA"
1114 rightsubnetwithin=10.1.0.0/24 # Sales DHCP range
1115 leftsubnet=10.0.0.0/24 # Sales subnet
1119 rightca="C=CH, O=ACME, OU=Research, CN=Research CA"
1120 rightsubnetwithin=10.1.1.0/24 # Research DHCP range
1121 leftsubnet=10.0.1.0/24 # Research subnet
1125 rightca="C=CH, O=ACME, CN=ACME Root CA"
1126 rightsubnetwithin=10.1.0.0/23 # Remote access DHCP range
1127 leftsubnet=10.0.2.100/32 # Web server
1128 rightprotoport=tcp # TCP protocol only
1129 leftprotoport=tcp/http # TCP port 80 only
1131 In the example above, the connection "sales" can be used by peers
1132 presenting certificates issued by the Sales CA, only. In the same way,
1133 the use of the connection "research" is restricted to owners of certificates
1134 issued by the Research CA. The connection "web" is open to both "Sales" and
1135 "Research" peers because the required "ACME Root CA" is the issuer of the
1136 Research and Sales intermediate CAs. If no rightca parameter is present
1137 then any valid certificate issued by one of the trusted CAs in
1138 /etc/ipsec.d/cacerts can be used by the peer.
1140 The leftca parameter usually doesn't have to be set explicitly because
1141 by default it is set to the issuer field of the certificate loaded via
1142 leftcert. The statement
1146 sets the CA requested from the peer to the CA used by the left side itself
1152 leftcert=mySalesCert.pem
1155 4.8 Sending certificate requests
1156 ----------------------------
1158 The presence of a rightca parameter also causes the CA to be sent as
1159 part of the certificate request message when strongSwan is the initiator.
1160 A special case occurs when strongSwan responds to a roadwarrior. If several
1161 roadwarrior connections based on different CAs are defined then all eligible
1162 CAs will be listed in Pluto
\92s certificate request message.
1165 4.9 IPsec policies based on group attributes
1166 ----------------------------------------
1168 X.509 attribute certificates are the most powerful mechanism for implementing
1169 IPsec security policies. The rightgroups parameter in a connection definition
1170 restricts the access to members of the listed groups only. An IPsec peer must
1171 have a valid attribute certificate issued by a trusted Authorization Authority
1172 and listing one of the requirede group attributes in order to get admitted.
1177 rightsubnetwithin=10.1.0.0/24 # Sales DHCP range
1178 leftsubnet=10.0.0.0/24 # Sales subnet
1182 rightgroups="Research"
1183 rightsubnetwithin=10.1.1.0/24 # Research DHCP range
1184 leftsubnet=10.0.1.0/24 # Research subnet
1188 rightgroups="Sales, Research"
1189 rightsubnetwithin=10.1.0.0/23 # Remote access DHCP range
1190 leftsubnet=10.0.2.100/32 # Web server
1191 rightprotoport=tcp # TCP protocol only
1192 leftprotoport=tcp/http # TCP port 80 only
1194 In the examples above membership of the group "Sales" is required for
1195 connection sales and membership of "Research" for connection research
1196 whereas connection web is accessible for both groups.
1198 Currently the attribute certificates of the peers must be loaded statically
1199 via the /etc/ipsec.d/acerts/ directory. In future releases of strongSwan it
1200 will be possible to fetch them from an LDAP directory server.
1203 5. Configuring certificates and CRLs
1204 ---------------------------------
1207 5.1 Installing the CA certificates
1208 ------------------------------
1210 X.509 certificates received by strongSwan during the IKE protocol are
1211 automatically authenticated by going up the trust chain until a self-signed
1212 root CA certificate is reached. Usually host certificates are directly signed
1213 by a root CA, but strongSwan also supports multi-level hierarchies with
1214 intermediate CAs in between. All CA certificates belonging to a trust chain
1215 must be copied in either binary DER or base64 PEM format into the directory
1217 /etc/ipsec.d/cacerts/
1220 5.2 Installing optional certificate revocation lists (CRLs)
1221 -------------------------------------------------------
1223 By copying a CA certificate into /etc/ipsec.d/cacerts/, automatically all user
1224 or host certificates issued by this CA are declared valid. Unfortunately
1225 private keys might get compromised inadvertently or intentionally, personal
1226 certificates of users leaving a company have to be blocked immediately, etc.
1227 To this purpose certificate revocation lists (CRLs) have been created. CRLs
1228 contain the serial numbers of all user or host certificates that have been
1229 revoked due to various reasons.
1231 After successful verification of the X.509 trust chain, Pluto searches its
1232 list of CRLs either obtained by loading them from the /etc/ipsec.d/crls/
1233 directory or fetching them dynamically from a HTTP or LDAP server for the
1234 presence of a CRL issued by the CA that has signed the certificate.
1236 If the serial number of the certificate is found in the CRL then the public key
1237 contained in the certificate is declared invalid and the IPSec SA will not be
1238 established. If no CRL is found or if the deadline defined in the nextUpdate
1239 field of the CRL has been reached, a warning is issued but the public key will
1240 nevertheless be accepted. CRLs must be stored either in binary DER or base64 PEM
1241 format in the crls directory. Section 7.3 will explain in detail how CRLs can
1242 be created using OpenSSL.
1245 5.3 Dynamic update of certificates and CRLs
1246 ---------------------------------------
1248 Pluto reads certificates and CRLs from their respective files during system
1249 startup and keeps them in memory in the form of chained lists. X.509
1250 certificates have a finite life span defined by their validity field. Therefore
1251 it must be possible to replace CA or OCSP certificates kept in system memory
1252 without disturbing established ISAKMP SAs. Certificate revocation lists should
1253 also be updated in the regular intervals indicated by the nextUpdate field in
1254 the CRL body. The following interactive commands allow the manual replacement
1255 of the various files:
1257 +---------------------------------------------------------------------------+
1258 | ipsec rereadsecrets reload file /etc/ipsec.secrets |
1259 |---------------------------------------------------------------------------|
1260 | ipsec rereadcacerts reload all files in /etc/ipsec.d/cacerts/ |
1261 |---------------------------------------------------------------------------|
1262 | ipsec rereadaacerts reload all files in /etc/ipsec.d/aacerts/ |
1263 |---------------------------------------------------------------------------|
1264 | ipsec rereadocspcerts reload all files in /etc/ipsec.d/ocspcerts/ |
1265 |---------------------------------------------------------------------------|
1266 | ipsec rereadacerts reload all files in /etc/ipsec.d/acerts/ |
1267 |---------------------------------------------------------------------------|
1268 | ipsec rereadcrls reload all files in /etc/ipsec.d/crls/ |
1269 |---------------------------------------------------------------------------|
1270 | ipsec rereadall ipsec rereadsecrets |
1276 |---------------------------------------------------------------------------|
1277 | ipsec purgeocsp purge the OCSP cache and fetching requests |
1278 +---------------------------------------------------------------------------+
1280 CRLs can also be automatically fetched from an HTTP or LDAP server by using
1281 the CRL distribution points contained in X.509 certificates. The command
1285 shows any pending fetch requests:
1287 Oct 31 00:29:53 2002, trials: 2
1288 issuer: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
1289 distPts: 'http://crl.strongswan.org/strongswan.crl'
1290 'ldap://ldap.strongswan.org/o=Linux strongSwan, c=CH
1291 ?certificateRevocationList?base
1292 ?(objectClass=certificationAuthority)'
1294 In the example above, an http and an ldap URL were extracted from a received
1295 end certificate. An independent thread then tries to fetch a CRL from the
1296 designated distribution points. The same thread also periodically checks
1297 if any loaded CRLs are about to expire. The check interval can be defined in
1298 the "config setup" section of the ipsec.conf file:
1301 crlcheckinterval=600
1303 In our example the thread wakes up every 600 seconds or 10 minutes in order
1304 to check the validity of the CRLs or to retry any pending fetch requests:
1308 Dec 19 09:35:31 2002, revoked certs: 40
1309 issuer: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
1310 distPts: 'http://crl.strongswan.org/strongswan.crl'
1311 updates: this Dec 19 09:35:00 2002
1312 next Dec 19 10:35:00 2002 warning (expires in 19 minutes)
1314 List of fetch requests:
1316 Dec 19 10:15:31 2002, trials: 1
1317 issuer: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
1318 distPts: 'http://crl.strongwan.org/strongswan.crl'
1320 The first trial to update a CRL is started 2*crlcheckinterval before the
1321 nextUpdate time, i.e. when less than 20 minutes are left in our practical
1322 example. When crlcheckinterval is set to 0 (this is also the default value
1323 when the parameter is not set in ipsec.conf) then the CRL checking and updating
1324 thread is not started and dynamic CRL fetching is disabled.
1327 5.4 Local caching of CRLs
1328 ---------------------
1330 The the ipsec.conf option
1335 activates the local caching of CRLs that were dynamically fetched from an
1336 HTTP or LDAP server. Cached copies are stored in /etc/ipsec.d/crls under a
1337 unique filename formed from the issuer's SubjectKeyIdentifier and the suffix .crl.
1339 With the cached copy the CRL is immediately available after pluto's startup.
1340 When the local copy is about to expire it is automatically replaced with an
1341 updated CRL fetched from one of the defined CRL distribution points.
1344 5.5 Online Certificate Status Protocol (OCSP)
1345 -----------------------------------------
1347 The Online Certificate Status Protocol is defined by RFC 2560. It can be
1348 used to query an OCSP server about the current status of an X.509 certificate
1349 and is often used as a more dynamic alternative to a static Certificate
1350 Revocation List (CRL). Both the OCSP request sent by the client and the OCSP
1351 response messages returned by the server are transported via a standard
1352 TCP/HTTP connection. Therefore cURL support must be enabled in pluto/Makefile:
1354 # Uncomment this line to enable OCSP fetching using HTTP
1357 In the simplest OCSP setup, a default URI under which the OCSP server for a
1358 given CA can be accessed is defined in ipsec.conf:
1361 crlcheckinterval=600
1364 cacert=strongswanCert.pem
1365 ocspuri=http://ocsp.strongswan.org:8880
1368 The HTTP port can be freely chosen. In our example we have assumed TCP port 8880.
1369 The crlcheckinterval must be set to a value different from zero. Otherwise the
1370 OCSP fetching thread will not be started.
1372 The well-known openssl-0.9.7 package from http://www.openssl.org implements
1373 an OCSP server that can be used in conjunction with an openssl-based Public
1374 Key Infrastructure. The OCSP client integrated into Pluto does not contain
1375 any OpenSSL code though, but is based on the existing ASN.1 functionality of
1378 The OpenSSL-based OCSP server is started with the following command:
1380 openssl ocsp -index index.txt -CA strongswanCert.pem -port 8880 \
1381 -rkey ocspKey.pem -rsigner ocspCert.pem \
1382 -resp_no_certs -nmin 60 -text
1384 The command consists of the parameters
1386 -index index.txt is a copy of the OpenSSL index file containing the list of
1387 all issued certificates. The certificate status in indext.txt
1388 is designated either by V for valid or R for revoked. If
1389 a new certificate is added or if a certificate is revoked
1390 using the openssl ca command, the OCSP server must be restarted
1391 in order for the changes in index.txt to take effect.
1393 -CA the CA certificate
1395 -port the HTTP port the OCSP server is listening on.
1397 -rkey the private key used to sign the OCSP response. The use of the
1398 sensitive CA private key is not recommended since this could
1399 jeopardize the security of your production PKI if the OCSP
1400 server is hacked. It is much better to generate a special
1401 RSA private key just for OCSP signing use instead.
1403 -rsigner the certificate of the OCSP server containing a public key which
1404 matches the private key defined by -rkey and which can be used by
1405 the client to check the trustworthiness of the signed OCSP response.
1407 -resp_no_certs With this option the OCSP signer certificate defined by
1408 -rsigner is not included in the OCSP response.
1410 -nmin the validity interval of an OCSP response given in minutes.
1411 2*crlcheckinterval before the expiration of the OCSP responses,
1412 a new query will by pro-actively started by the Pluto fetching thread.
1414 If nmin is missing or set to zero then the default validity interval
1415 compiled into Pluto will be 2 minutes, leading to a quasi one-time
1416 use of the OCSP status response which will not be periodically
1417 refreshed by the fetching thread. In conjunction with the parameter
1418 setting "strictcrlpolicy=yes" a real-time certificate status query
1419 can be implemented in this way.
1421 -text This option activates a verbose logging output, showing the contents
1422 of both the received OCSP request and sent OCSP response.
1424 How does Pluto get hold of the OCSP signer certificate? There are two
1427 Either you put the OCSP certificate into the default directory
1429 /etc/ipsec.d/ocspcerts
1431 or alternatively Pluto can receive it as part of the OCSP response from the
1432 remote OCSP server. In the latter case, how can Pluto make sure that
1433 the server has indeed been authorized by the CA to deal out certificate status
1434 information? In order to ascertain the OCSP signer capability, an extended
1435 key usage attribute can be included in the OCSP server certificate. Just
1436 insert the parameter
1438 extendedKeyUsage=OCSPSigner
1440 in the [ usr_cert ] section of your openssl.cnf configuration file before
1441 the CA signs the OCSP server certificate.
1443 For a given CA the corresponding ca section in ipsec.conf (see section 7) allows
1444 to define the URI of a single OCSP server. As an alternative an OCSP URI can be
1445 embedded into each host and user certificate by putting the line
1447 authorityInfoAccess = OCSP;URI:http://ocsp.strongswan.org:8880
1449 into the [ usr_cert ] section of your openssl.cnf configuration file.
1450 If an OCSP authorityInfoAccess extension is present in a certificate then this
1451 record overrides the default URI defined by the ca section.
1457 By default Pluto is quite tolerant concerning the handling of CRLs. It is not
1458 mandatory for a CRL to be present in /etc/ipsec.d/crls and if the expiration
1459 date defined by the nextUpdate field of a CRL has been reached just a warning
1460 is issued but a peer certificate will always be accepted if it has not been
1463 If you want to enforce a stricter CRL policy then you can do this by setting
1464 the "strictcrlpolicy" option. This is done in the "config setup" section
1465 of the ipsec.conf file:
1471 A certificate received from a peer will not be accepted if no corresponding
1472 CRL or OCSP response is available. And if an ISAKMP SA re-negotiation takes
1473 place after the nextUpdate deadline has been reached, the peer certificate
1474 will be declared invalid and the cached RSA public key will be deleted, causing
1475 the connection in question to fail. Therefore if you are going to use the
1476 "strictcrlpolicy=yes" option, make sure that the CRLs will always be updated
1477 in time. Otherwise a total standstill would ensue.
1479 As mentioned earlier the default setting is "strictcrlpolicy=no"
1482 5.7 Configuring the peer side using locally stored certificates
1483 -----------------------------------------------------------
1485 If you don't want to use trust chains based on CA certificates as proposed in
1486 section 4.3 you can alternatively import trusted peer certificates directly
1487 into Pluto. Thus you do not have to rely on the certificate to be transmitted
1488 by the peer as part of the IKE protocol.
1490 With the conn %default section defined in section 4.1 and the use of the
1491 rightcert keyword for the peer side, the connection definitions in section 4.3
1492 can alternatively be written as
1496 rightid=@sun.strongswan.org
1497 rightcert=sunCert.cer
1501 rightcert=carolCert.der
1503 If the peer certificates are loaded locally then there is no sense in sending
1504 any certificates to the other end via the IKE Main Mode protocol. Especially
1505 if self-signed certificates are used which wouldn't be accepted any way by
1506 the other side. In these cases it is recommended to add
1510 to the connection definition[s] in order to avoid the sending of the host's
1511 own certificate. The default value is
1513 leftsendcert=always.
1515 If a peer certificate contains a subjectAltName extension, then an alternative
1516 rightid type can be used, as the example "conn sun" shows. If no rightid
1517 entry is present then the subject distinguished name contained in the
1518 certificate is taken as the ID.
1520 Using the same rules concerning pathnames that apply to strongSwan's own
1521 certificates, the following two definitions are also valid for trusted peer
1524 rightcert=peercerts/carolCert.der
1528 rightcert=/usr/ssl/certs/carolCert.der
1531 6. Installing the private key - ipsec.secrets
1532 ------------------------------------------
1534 6.1 Loading private key files in PKCS#1 format
1535 ------------------------------------------
1537 Besides strongSwan's raw private key format strongSwan has been enabled to
1538 load RSA private keys in the PKCS#1 file format. The key files can be
1539 optionally secured with a passphrase.
1541 RSA private key files are declared in /etc/ipsec.secrets using the syntax
1543 : RSA <my keyfile> "<optional passphrase>"
1545 The key file can be either in base64 PEM-format or binary DER-format. The
1546 actual coding is detected "automagically" by Pluto. The example
1550 uses a relative pathname. In this case Pluto will look for the key file
1553 /etc/ipsec.d/private
1555 As an alternative an absolute pathname can be given as in
1557 : RSA /usr/ssl/private/moonKey.pem
1559 In both cases make sure that the key files are root readable only.
1561 Often a private key must be transported from the Certification Authority
1562 where it was generated to the target security gateway where it is going
1563 to be used. In order to protect the key it can be encrypted with 3DES
1564 using a symmetric transport key derived from a cryptographically strong
1567 openssl genrsa -des3 -out moonKey.pem 1024
1569 Because of the weak security, key files protected by single DES will not
1570 be accepted by Pluto!!!
1572 Once on the security gateway the private key can either be permanently
1573 unlocked so that it can be used by Pluto without having to know a
1576 openssl rsa -in moonKey.pem -out moonKey.pem
1578 or as an option the key file can remain secured. In this case the passphrase
1579 unlocking the private key must be added after the pathname in
1582 : RSA moonKey.pem "This is my passphrase"
1584 Some CAs distribute private keys embedded in a PKCS#12 file. Since Pluto
1585 is not able yet to read this format directly, the private key part must
1586 first be extracted using the command
1588 openssl pkcs12 -nocerts -in moonCert.p12 -out moonKey.pem
1590 if the key file moonKey.pem is to be secured again by a passphrase, or
1592 openssl pkcs12 -nocerts -nodes -in moonCert.p12 -out moonKey.pem
1594 if the private key is to be stored unlocked.
1597 6.2 Entering passphrases interactively
1598 ----------------------------------
1600 On a VPN gateway you would want to put the passphrase protecting the private
1601 key file right into /etc/ipsec.secrets as described in the previous paragraph,
1602 so that the gateway can be booted in unattended mode. The risk of keeping
1603 unencrypted secrets on a server can be minimized by putting the box into a
1604 locked room. As long as no one can get root access on the machine the private
1607 On a mobile laptop computer the situation is quite different. The computer can
1608 be stolen or the user is leaving it unattended so that unauthorized persons
1609 can get access to it. In theses cases it would be preferable not to keep any
1610 passphrases openly in /etc/ipsec.secrets but to prompt for them interactively
1611 instead. This is easily done by defining
1613 : RSA moonKey.pem %prompt
1615 Since strongSwan is usually started during the boot process, usually no
1616 interactive console windows is available which can be used by Pluto to
1617 prompt for the passphrase. This must be initiated by the user by typing
1621 which actually is an alias for the existing command
1625 and which causes the prompt
1627 need passphrase for '/etc/ipsec.d/private/moonKey.pem'
1630 to appear. If the passphrase was correct and the private key file could be
1631 successfully decrypted then
1635 results. Otherwise the prompt
1637 invalid passphrase, please try again
1640 will give you another try. Entering a carriage return will abort the
1641 the passphrase prompting.
1644 6.3 Multiple private keys
1645 ---------------------
1647 strongSwan supports multiple private keys. Since the connections defined
1648 in ipsec.conf can find the correct private key based on the public key
1649 contained in the certificate assigned by leftcert, default private key
1650 definitions without specific IDs can be used
1652 : RSA myKey1.pem "<optional passphrase1>"
1654 : RSA myKey2.pem "<optional passphrase2>"
1657 7. Configuring CA properties - ipsec.conf
1658 --------------------------------------
1660 Besides the definition of IPsec connections the ipsec.conf file can also
1661 be used to configure a few properties of the certification authorities
1662 needed to establish the X.509 trust chains. The following example shows
1663 the parameters that are currently available:
1666 cacert=strongswanCert.pem
1667 ocspuri=http://ocsp.strongswan.org:8880
1668 crluri=http://crl.strongswan.org/strongswan.crl'
1669 crluri2="ldap:///O=Linux strongSwan, C=CH?certificateRevocationList"
1670 ldaphost=ldap.strongswan.org
1673 In a similar way as conn sections are used for connection definitions, an
1674 arbitrary number of optional ca sections define the basic properties of CAs.
1676 Each ca section is named with a unique label
1680 The only mandatory parameter is
1682 cacert=strongswanCert.pem
1684 which points to the CA certificate which usually resides in the default
1685 directory /etc/ipsec.d/cacerts/ but could also be retrieved via an absolute
1686 path name. If the CA certificate is stored on a smartcard then the
1689 cacert=%smartcard#<n>
1693 cacert=%smartcard<optional slot nr>:<key id>
1695 can be used. The selection of smartcard slots is described in more detail
1698 From the certificate the CA's distinguished name and the serial number
1699 is extracted. If an optional subjectKeyAuthentifier is present then it can
1700 be used to uniquely identify consecutive generations of CA certificates
1701 carrying the same distinguished name.
1705 ocspuri=http://ocsp.strongswan.org:8880
1707 allows to define an individual OCSP server per CA. Also up to two additional
1708 CRL distribution points (CDPs) can be defined
1710 crluri=http://crl.strongswan.org/strongswan.crl'
1711 crluri2="ldap:///O=Linux strongSwan, C=CH?certificateRevocationList"
1713 which are added to any CDPs already present in the received certificates
1714 themselves. The last parameter
1716 ldaphost=ldap.strongswan.org
1718 can be used to fill in the actual server name in LDAP CDPs where the host is missing
1719 as e.g. in the crluri2 above. In future releases this ldaphost parameter might be used
1720 to retrieve user, host and attribute certificates.
1723 With the auto=add statement the ca definition is automatically loaded into Pluto during
1724 system startup. Setting auto=ignore will ignore the ca section. Additional ca definitions
1725 can be loaded from ipsec.conf during runtime with the command
1727 ipsec auto --type ca --add strongswan-sales
1731 ipsec auto --type ca --delete strongswan-sales
1733 deletes the labeled ca entry. And finally the command
1735 ipsec auto --type ca --replace strongswan
1737 first deletes the old definition in Pluto's memory and then loads the updated version
1738 from ipsec.conf. Any parameters which appear in several ca definitions can be put in
1739 a common ca %default section
1742 ldaphost=ldap.strongswan.org
1745 8. Smartcard support
1748 8.1 Configuring a smartcard-based connection
1749 ----------------------------------------
1751 Defining a smartcard-based connection in ipsec.conf is easy:
1755 rightid=@sun.strongswan.org
1760 In most cases there is a single smartcard reader or cryptotoken and only one
1761 RSA private key safely stored on the crypto device. Thus usually the entry
1765 which stands for the full notation
1767 leftcert=%smartcard#1
1769 is sufficient where the first certificate/private key object enumerated by
1770 the PKCS#11 module is used. If several certificate/private key objects are
1771 present then the nth object can be selected using
1773 leftcert=%smartcard#<n>
1779 gives an overview over all certificate objects made available by the PKCS#11
1780 module.CA certificates are automatically available as trust anchors.
1782 As an alternative the certificate ID and/or the slot number defined by
1783 the PKCS#11 standard can be specified using the notation
1785 leftcert=%smartcard<optional slot nr>:<key id in hex format>
1789 leftcert=%smartcard:50
1791 will look in all available slots for ID 0x50 starting with the first slot
1792 (usually slot 0) whereas
1794 leftcert=%smartcard4:50
1796 will directly check slot 4 (which is usually the first slot on the second
1797 reader/token when using the OpenSC library) for a key with ID 0x50.
1800 8.2 Entering the PIN code
1801 ---------------------
1803 Since the smartcard signing operation needed to sign the hash with the
1804 RSA private key during IKE Main Mode is protected by a PIN code,
1805 the secret PIN must be made available to Pluto.
1807 For gateways that must be able to start IPsec tunnels automatically in
1808 unattended mode after a reboot, the secret PIN can be stored statically
1811 : PIN %smartcard "12345678"
1813 or with the general notation
1815 : PIN %smartcard#<n> "<PIN code>"
1819 : PIN %smartcard<optional slot nr>:<key id> "<PIN code>"
1821 On personal notebooks that could get stolen, you wouldn't want to store
1822 your PIN in ipsec.secrets. Thus the alternative form
1824 : PIN %smartcard %prompt
1826 will prompt you for the PIN when you start up the first IPsec connection
1831 The auto command calls the whack function which in turn communicates with
1832 Pluto over a socket. Since the whack function call is executed from a command
1833 window, Pluto can prompt you for the PIN over this socket connection.
1834 Unfortunately roadwarrior connections which just wait passively for peers
1835 cannot be initiated via the command window:
1840 leftcert=%smartcard4:50
1843 But if there is a corresponding entry
1845 : PIN %smartcard4:50 %prompt
1847 in ipsec.secrets, then the standard command
1855 can be used to enter the PIN code for this connection interactively.
1861 can be executed at any time to check the current status of the PIN code[s].
1864 8.3 PIN-pad equipped smartcard readers
1865 ----------------------------------
1867 Smartcard readers with an integrated PIN-pad offer an increased security
1868 level because the PIN entry cannot be sniffed on the host computer e.g.
1869 by a surrepticiously installed key logger. In order to tell pluto not to
1870 prompt for the PIN on the host itself, the entry
1872 : PIN %smartcard:50 %pinpad
1874 can be used in ipsec.secrets. Because the key pad does not cache the PIN in
1875 the smartcard reader, it must be entered for every PKCS #11 session login.
1876 By default pluto does a session logout after every RSA signature. In order
1877 to avoid the repeated entry of the PIN code during the periodic IKE main
1878 mode rekeyings, the following parameter can be set in the config setup
1879 section of ipsec.conf:
1884 The default setting is pkcs11keepstate=no.
1887 8.4 Configuring a smartcard with pkcsc15-init
1888 -----------------------------------------
1890 strongSwan's smartcard solution is based on the PKCS#15 "Cryptographic Token
1891 Information Format Standard" fully supported by OpenSC library functions.
1894 pkcs15-init --erase-card --create-pkcs15
1896 a fresh PKCS#15 file structure is created on a smartcard or cryptotoken.
1897 With the next command
1899 pkcs15-init --auth-id 1 --store-pin --pin "12345678" --puk "87654321"
1902 a secret PIN code with auth-id 1 is stored in an unretrievable location on
1903 the smart card. The PIN will protect the RSA signing operation. If the PIN
1904 is entered incorrectly more than three times the smartcard will be locked
1905 and the PUK code can be used to unlock the card again.
1907 Next the RSA private key is transferred to the smartcard
1909 pkcs15-init --auth-id 1 --store-private-key myKey.pem [--id 45]
1911 By default the PKCS#15 smartcard record will be assigned the id 45.
1912 Using the --id option multiple key records can be stored on a smartcard.
1914 At last we load the matching X.509 certificate onto the smartcard
1916 pkcs15-init --auth-id 1 --store-certificate myCert.pem [--id 45]
1918 The pkcs15-tool can now be used to verify the contents of the smartcard.
1920 pkcs15-tool --list-pins --list-keys --list-certificates
1922 If everything is ok then you are ready to use the generated PKCS#15
1923 structure with strongSwan.
1925 8.5 PKCS#11 proxy functions
1926 -----------------------
1928 With the setting pkcs11keepstate=yes some PKCS#11 implementations
1929 (e.g. OpenSC) will lock the access to the smartcard as soon as pluto has
1930 opened a session and will thus prevent other application from sharing the
1931 smartcard resource. In order to solve this locking problem, strongSwan
1932 offers a PKCS#11 proxy service making use of the whack socket communication
1933 channel. The setting
1938 will enable the proxy mode that is disabled by default.
1940 Currently two smartcard operations are supported: RSA encryption and
1941 RSA decryption. The notation is as follows:
1943 ipsec scdecrypt <encrypted data>
1944 [--inbase 16|hex|64|base64|256|text|ascii]
1945 [--outbase 16|hex|64|base64|256|text|ascii]
1948 The default settings for inbase and outbase is hexadecimal.
1949 Thus the simplest call has the form
1951 ipsec scdecrypt bb952b71920094ce0696ef9b8b26...12e6
1953 and the returned result might be a decrypted 128 bit AES key
1955 000 8836362e030e6707c32ffaa0bdad5540
1957 The leading three characters represent the return code of the whack channel
1958 with 000 signifying that no error has occured. Here is another example showing
1959 the use of the inbase and outbase attributes
1961 ipsec scdecrypt m/ewDnTs0k...woE= --inbase base64 --outbase text
1963 where the result has the form
1965 000 This is a secret
1967 By default the first RSA private key found by the PKCS#11 enumeration is
1968 used. If a different key should be selected then the notation introduced
1969 in sections 8.1 and 8.2 can be used:
1971 --keyid %smartcard:50
1972 --keyid %smartcard4:50
1973 --keyid %smartcard#3
1975 with --keyid %smartcard#1 being the default. If supported by the smartcard
1976 and PKCS#11 library RSA encryption can be used with the notation
1978 ipsec scencrypt <plaintext data>
1979 [--inbase 16|hex|64|base64|256|text|ascii]
1980 [--outbase 16|hex|64|base64|256|text|ascii]
1985 ipsec scencrypt "This is a secret" --inbase ascii --outbase 64
1987 returning the expected output
1989 000 m/ewDnTs0k...woE=
1992 9. Configuring the clients
1993 -----------------------
1998 A strongSwan to strongSwan connection is symmetrical. Any of the four defined
1999 ID types can be used, even different types on either end of the connection,
2000 although this wouldn't make much sense.
2002 +--------------------------------------------------------------+
2003 | Connection Definition ID type subjectAltName |
2004 |--------------------------------------------------------------|
2005 | rightid (strongSwan) DER_ASN1_DN - |
2007 | USER_FQDN email: |
2009 |--------------------------------------------------------------|
2010 | leftid (strongSwan) DER_ASN1_DN - |
2012 | USER_FQDN email: |
2014 +--------------------------------------------------------------+
2020 Use the file peerCert.p12 to import PGPnet's X.509 certificate, the CA
2021 certificate, plus the encrypted private key in binary PKCS#12 format into the
2022 PGPkey tool. You will be prompted for the passphrase securing the private key.
2024 Use the file myCert.pem to import the X.509 certificate of the strongSwan
2025 security gateway into the PGPkey tool. The PGPkeyTool does not accept X.509
2026 certificates in binary DER format, so it must be imported in base64 format:
2028 -----BEGIN CERTIFICATE-----
2032 -----END CERTIFICATE-----
2034 Make sure that there is no human-readable listing of the X.509 certificate in
2037 -----BEGIN CERTIFICATE-----
2039 otherwise PGPnet will refuse to load the *.PEM file. Any surplus lines can
2040 either be deleted by loading the certificate into a text editor or you can
2043 openssl x509 -in myCert.pem -out myCert.pem
2045 to achieve the same effect.
2047 With authentication based on X.509 certificates, PGPnet always sends the ID
2048 type DER_ASN1_DN, therefore rightid in the connection definition of the
2049 strongSwan security gateway must be an ASN.1 distinguished name.
2051 In the receiving direction PGPnet accepts all four ID types from strongSwan.
2053 +--------------------------------------------------------------+
2054 | Connection Definition ID type subjectAltName |
2055 |--------------------------------------------------------------|
2056 | rightid (PGPnet) DER_ASN1_DN - |
2057 |--------------------------------------------------------------|
2058 | leftid (strongSwan) DER_ASN1_DN - |
2060 | USER_FQDN email: |
2062 +--------------------------------------------------------------+
2065 9.3 SafeNet/Soft-PK/Soft-Remote
2066 ---------------------------
2068 SafeNet/Soft-PK and SafeNet/Soft-Remote can be configured to send their
2069 identity either as DER_ASN1_DN, IPV4_ADDR, FQDN, or USER_FQDN.
2070 In the receiving direction SafeNet/Soft-PK and SafeNet/Soft-Remote
2071 accept all four ID types coming from strongSwan.
2073 +--------------------------------------------------------------+
2074 | Connection Definition ID type subjectAltName |
2075 |--------------------------------------------------------------|
2076 | rightid (SafeNet/Soft-PK) DER_ASN1_DN - |
2078 | USER_FQDN email: |
2080 |--------------------------------------------------------------|
2081 | leftid (strongSwan) DER_ASN1_DN - |
2083 | USER_FQDN email: |
2085 +--------------------------------------------------------------+
2091 SSH Sentinel sends its identity as DER_ASN1_DN if the subjectAltName field of
2092 its certificate is empty. If a subjectAltName field is present, then the
2093 corresponding type IPV4_ADDR, FQDN, or USER_FQDN is automatically chosen.
2094 With several subjectAltName entries, the precedence of the different ID types
2095 is not quite clear. In the receiving direction SSH Sentinel accepts all four
2096 ID types from strongSwan.
2098 +--------------------------------------------------------------+
2099 | Connection Definition ID type subjectAltName |
2100 |--------------------------------------------------------------|
2101 | rightid (SSH Sentinel) DER_ASN1_DN - |
2103 | USER_FQDN email: |
2105 |--------------------------------------------------------------|
2106 | leftid (strongSwan) DER_ASN1_DN - |
2108 | USER_FQDN email: |
2110 +--------------------------------------------------------------+
2116 Windows 2000 and Windows XP always send the ID type DER_ASN1_DN,
2117 therefore rightid in the connection definition of the strongSwan
2118 security gateway must be an ASN.1 distinguished name.In the
2119 receiving direction Windows 2000/XP accepts all four ID types
2122 +--------------------------------------------------------------+
2123 | Connection Definition ID type subjectAltName |
2124 |--------------------------------------------------------------|
2125 | rightid (Windows 2000/XP) DER_ASN1_DN - |
2126 |--------------------------------------------------------------|
2127 | leftid (strongSwan) DER_ASN1_D - |
2129 | USER_FQDN email: |
2131 +--------------------------------------------------------------+
2134 10. Monitoring functions
2135 --------------------
2137 strongSwan offers the following monitoring functions:
2142 lists all IKE and ESP cryptographic algorithms that are currently
2143 registered with strongSwan.
2145 The a listing has the following form:
2147 List of registered IKE Encryption Algorithms:
2149 #3 OAKLEY_BLOWFISH_CBC, blocksize: 64, keylen: 128-128-256
2150 #5 OAKLEY_3DES_CBC, blocksize: 64, keylen: 192-192-192
2151 #7 OAKLEY_AES_CBC, blocksize: 128, keylen: 128-128-256
2152 #65004 OAKLEY_SERPENT_CBC, blocksize: 128, keylen: 128-128-256
2153 #65005 OAKLEY_TWOFISH_CBC, blocksize: 128, keylen: 128-128-256
2154 #65289 OAKLEY_TWOFISH_CBC_SSH, blocksize: 128, keylen: 128-128-256
2156 List of registered IKE Hash Algorithms:
2158 #1 OAKLEY_MD5, hashsize: 128
2159 #2 OAKLEY_SHA, hashsize: 160
2160 #4 OAKLEY_SHA2_256, hashsize: 256
2161 #6 OAKLEY_SHA2_512, hashsize: 512
2163 List of registered IKE DH Groups:
2165 #2 OAKLEY_GROUP_MODP1024, groupsize: 1024
2166 #5 OAKLEY_GROUP_MODP1536, groupsize: 1536
2167 #14 OAKLEY_GROUP_MODP2048, groupsize: 2048
2168 #15 OAKLEY_GROUP_MODP3072, groupsize: 3072
2169 #16 OAKLEY_GROUP_MODP4096, groupsize: 4096
2170 #17 OAKLEY_GROUP_MODP6144, groupsize: 6144
2171 #18 OAKLEY_GROUP_MODP8192, groupsize: 8192
2173 List of registered ESP Encryption Algorithms:
2175 #3 ESP_3DES, blocksize: 64, keylen: 168-168
2176 #7 ESP_BLOWFISH, blocksize: 64, keylen: 96-128
2177 #12 ESP_AES, blocksize: 128, keylen: 128-256
2178 #252 ESP_SERPENT, blocksize: 128, keylen: 128-256
2179 #253 ESP_TWOFISH, blocksize: 128, keylen: 128-256
2181 List of registered ESP Authentication Algorithms:
2183 #1 AUTH_ALGORITHM_HMAC_MD5, keylen: 128-128
2184 #2 AUTH_ALGORITHM_HMAC_SHA1, keylen: 160-160
2185 #5 AUTH_ALGORITHM_HMAC_SHA2_256, keylen: 256-256
2186 #7 AUTH_ALGORITHM_HMAC_SHA2_512, keylen: 512-512
2191 ipsec listpubkeys [--utc]
2193 lists all public keys currently installed in the chained list of public
2194 keys. These keys were statically loaded from ipsec.conf or aquired either
2195 from received certificates or retrieved from secure DNS servers using
2198 The public key listing has the following form:
2200 Feb 11 14:40:18 2005, 2048 RSA Key AwEAAa+uL,
2201 until Sep 09 13:17:25 2009 ok
2202 ID_FQDN '@moon.strongswan.org'
2203 issuer: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
2205 Feb 11 14:40:18 2005, 2048 RSA Key AwEAAa+uL,
2206 until Sep 09 13:17:25 2009 ok
2207 ID_DER_ASN1_DN 'C=CH, O=Linux strongSwan, CN=moon.strongswan.org'
2208 issuer: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
2210 Feb 11 13:36:53 2005, 2048 RSA Key AwEAAbgbh,
2211 until Dec 31 22:43:18 2009 ok
2212 ID_USER_FQDN 'carol@strongswan.org'
2213 issuer: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
2218 - the date the public key was installed either in local time or UTC (--utc)
2219 - the modulus size of the RSA key in bits
2220 - a keyID consisting of 9 base64 symbols representing the public exponent
2221 and the most significant bits of the modulus
2222 - the expiration date of the public key (extracted from the certificate)
2223 - the type and value of the ID associated with the public key.
2224 - the issuer of the certificate the public key was extracted from.
2225 - the serial number of the certificate the public key was extracted from.
2227 A public key can be associated with several IDs, e.g. using subjectAltNames
2228 in certificates and an ID can possess several public keys, e.g. retrieved
2229 from a secure DNS server.
2234 ipsec listcerts [--utc]
2236 lists all local certificates, both strongSwan's own and those of
2237 trusted peer loaded via leftcert and rightcert, respectively.
2239 The output has the form
2241 Feb 11 13:36:47 2005, count: 4
2242 subject: 'C=CH, O=Linux strongSwan, CN=moon.strongswan.org'
2243 issuer: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
2245 pubkey: 2048 RSA Key AwEAAa+uL, has private key
2246 validity: not before Sep 10 13:17:25 2004 ok
2247 not after Sep 09 13:17:25 2009 ok
2248 subjkey: e5:e4:10:87:6c:2a:c4:be:ad:85:49:42:a6:de:76:58:30:3a:9f:c1
2249 authkey: 5d:a7:dd:70:06:51:32:7e:e7:b6:6d:b3:b5:e5:e0:60:ea:2e:4d:ef
2254 - the date the certificate was installed either in local time or UTC (--utc)
2255 - the count shows how many connections refer to this certificate
2256 - the subject of the certificate
2257 - the issuer of the certificate
2258 - the serial number of the certificate
2259 - the size and keyid of the RSA public key contained in the certificate.
2260 the label "has private key" indicates that a matching RSA private key
2261 has been found, defined or loaded in ipsec.secrets.
2262 - the label "on smartcard" indicates that the certificate was loaded from
2263 a smartcard or cryptotoken and that most probably a matching RSA private
2264 key also resides on-card.
2265 - the validity of the CA certificate expressed either in local time or
2266 UTC (--utc). The validity is checked automatically resulting either
2267 in an "ok" message or a "fatal" error message.
2268 - the optional subjectKeyIdentifier extension which is a 20 byte SHA-1 hash
2269 over the certificate's public key.
2270 - the optional authorityKeyIdentifier extension which is a 20 byte SHA-1 hash
2271 over the public key of the issuer who signed the certificate.
2272 - the serial number of the issuer's certificate.
2277 ipsec listcacerts [--utc]
2279 lists all CA certificates that have been either been loaded from the directory
2280 /etc/ipsec.d/cacerts/ or received via the IKE protocol. The output has the form
2282 Feb 11 13:36:52 2005, count: 1
2283 subject: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
2284 issuer: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
2286 pubkey: 2048 RSA Key AwEAAb/yX
2287 validity: not before Sep 10 13:01:45 2004 ok
2288 not after Sep 08 13:01:45 2014 ok
2289 subjkey: 5d:a7:dd:70:06:51:32:7e:e7:b6:6d:b3:b5:e5:e0:60:ea:2e:4d:ef
2290 authkey: 5d:a7:dd:70:06:51:32:7e:e7:b6:6d:b3:b5:e5:e0:60:ea:2e:4d:ef
2295 - the date the CA certificate was installed either in local time or UTC (--utc)
2296 - the count is always set to 1
2297 - the subject of the CA certificate
2298 - the issuer of the CA certificate
2299 - the serial number of the CA certificate
2300 - the size and keyid of the RSA public key contained in the certificate.
2301 - the validity of the CA certificate expressed either in local time or
2302 UTC (--utc). The validity is checked automatically resulting either
2303 in an "ok" message or a "fatal" error message.
2304 - the optional subjectKeyIdentifier extension which is a 20 byte SHA-1 hash
2305 over the CA certificate's public key.
2306 - the optional authorityKeyIdentifier extension which is a 20 byte SHA-1 hash
2307 over the public key of the issuer who signed the CA certificate.
2308 For Root CA certificates the authorityKeyIdentifier and subjectKeyIdentifier
2309 fields must be equal.
2310 - the serial number of the issuer's certificate.
2315 ipsec listaacerts [--utc]
2317 lists all Authorization Authority certificates that have been loaded from
2318 the directory /etc/ipsec.d/aacerts/.
2319 The output has the form
2321 Dec 20 13:29:55 2004, count: 1
2322 subject: 'C=CH, O=strongSec GmbH, CN=strongSec Authorization Authority'
2323 issuer: 'C=CH, O=strongSec GmbH, CN=strongSec Root CA'
2325 pubkey: 2048 RSA Key AwEAAfazH
2326 validity: not before Aug 24 13:41:56 2003 ok
2327 not after Aug 23 13:41:56 2005 ok
2328 subjkey: 56:89:b9:28:c9:1b:a0:00:7f:50:9d:ec:28:75:23:c1:1e:d1:dd:90
2329 authkey: af:80:d5:c6:02:1c:96:78:b3:85:a5:65:a2:23:fd:ad:cf:e2:55:b2
2334 - the date the AA certificate was installed either in local time or UTC (--utc)
2335 - the count is always set to 1
2336 - the subject of the AA certificate
2337 - the issuer of the AA certificate
2338 - the serial number of the AA certificate
2339 - the size and keyid of the RSA public key contained in the certificate.
2340 - the validity of the AA certificate expressed either in local time or
2341 UTC (--utc). The validity is checked automatically resulting either
2342 in an "ok" message or a "fatal" error message.
2343 - the optional subjectKeyIdentifier extension which is a 20 byte SHA-1 hash
2344 over the AA certificate's public key.
2345 - the optional authorityKeyIdentifier extension which is a 20 byte SHA-1 hash
2346 over the public key of the issuer who signed the AA certificate.
2347 - the serial number of the issuer's certificate.
2352 ipsec listocspcerts [--utc]
2354 lists all OCSO signer certificates that have been either loaded from
2355 /etc/ipsec.d/ocspcerts/ or have been received included in the OCSP server
2356 response. The output has the form
2358 Feb 09 22:56:17 2005, count: 1
2359 subject: 'C=CH, O=Linux strongSwan, OU=OCSP, CN=ocsp.strongswan.org'
2360 issuer: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
2362 pubkey: 2048 RSA Key AwEAAaonT
2363 validity: not before Nov 19 17:29:28 2004 ok
2364 not after Nov 18 17:29:28 2009 ok
2365 subjkey: 88:07:0a:b8:ae:c7:c1:07:5c:be:68:6a:c4:a5:7f:81:1f:37:b5:56
2366 authkey: 5d:a7:dd:70:06:51:32:7e:e7:b6:6d:b3:b5:e5:e0:60:ea:2e:4d:ef
2371 - the date the OCSP signer certificate was installed either in local time
2373 - the count is always set to 1
2374 - the subject of the OCSP signer certificate
2375 - the issuer of the OCSP signer certificate
2376 - the serial number of the OCSP signer certificate
2377 - the size and keyid of the RSA public key contained in the certificate.
2378 - the validity of the OCSP signer certificate expressed either in local time
2379 or UTC (--utc). The validity is checked automatically resulting either
2380 in an "ok" message or a "fatal" error message.
2381 - the optional subjectKeyIdentifier extension which is a 20 byte SHA-1 hash
2382 over the OCSP signer certificate's public key.
2383 - the optional authorityKeyIdentifier extension which is a 20 byte SHA-1 hash
2384 over the public key of the issuer who signed the OCSP certificate.
2385 - the serial number of the issuer's certificate.
2390 ipsec listacerts [--utc]
2392 lists all X.509 attribute certificates that have been loaded from the directory
2393 /etc/ipsec.d/acerts/.
2394 The output has the form
2396 Dec 20 13:29:56 2004
2397 holder: 'C=CH, O=strongSec GmbH, CN=Andreas Steffen'
2398 hissuer: 'C=CH, O=strongSec GmbH, CN=strongSec Root CA'
2400 groups: Research, Sales
2401 issuer: 'C=CH, O=strongSec GmbH, CN=strongSec Authorization Authority'
2403 validity: not before Dec 19 14:51:38 2004 ok
2404 not after Dec 20 14:51:38 2004 fatal (expired)
2405 authkey: 56:89:b9:28:c9:1b:a0:00:7f:50:9d:ec:28:75:23:c1:1e:d1:dd:90
2410 - the date the attribute certificate was installed either in local time
2412 - the holder of the attribute certificate
2413 - the issuer of holder's certificate
2414 - the serial number of the holder's certificate
2415 - the group attributes
2416 - the issuing Authorization Authority of the attribute certificate
2417 - the serial number of the attribute certificate
2418 - the validity of the attribute certificate expressed either in local time or
2419 UTC (--utc). The validity is checked automatically resulting either
2420 in an "ok" message or a "fatal" error message.
2421 - an authorityKeyIdentifier extension which is a 20 byte SHA-1 hash
2422 over the public key of the issuing Authorization Authority
2423 - the serial number of the AA certificate.
2428 ipsec listgroups [--utc]
2430 lists all group attributes either defined in right|leftgroups statements
2431 in ipsec.conf or contained in loaded X.509 attribute certificates.
2432 The output has the form
2434 Dec 20 13:29:55 2004, count: 4
2436 Dec 20 13:30:04 2004, count: 1
2438 Dec 20 13:29:55 2004, count: 3
2443 - the date the group attribute was first installed either in local time
2445 - the count shows how many times the attribute is used
2451 ipsec listcainfos [--utc]
2453 lists the properties defined by the ca definition sections in ipsec.conf.
2454 The output has the form
2456 Jun 08 22:31:37 2004, "strongswan"
2457 authname: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
2458 ldaphost: 'ldap.strongswan.org'
2459 ocspuri: 'http://ocsp.strongswan.org:8880'
2460 distPts: 'http://crl.strongswan.org/strongswan.crl'
2461 'ldap:///O=Linux strongSwan, C=CH?certificateRevocationList'
2462 authkey: 5d:a7:dd:70:06:51:32:7e:e7:b6:6d:b3:b5:e5:e0:60:ea:2e:4d:ef
2467 - the date the CA definition was loaded either in local time or UTC (--utc)
2468 - the name of the ca section
2469 - the distinguished name of the CA
2470 - an optional default ldap host for the CA
2471 - an optional OCSP URI
2472 - a maximum of two optional CRL distribution points
2473 - the optional authorityKeyIdentifier extension which is a 20 byte SHA-1 hash
2474 over the public key of the CA.
2475 - the serial number of the CA.
2480 ipsec listcrls [--utc]
2482 lists all CRLs that have been loaded from /etc/ipsec.d/crls/.
2483 The output has the form
2485 Feb 11 13:37:00 2005, revoked certs: 1
2486 issuer: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
2487 distPts: 'http://crl.strongswan.org/strongswan.crl'
2488 updates: this Feb 08 07:46:29 2005
2489 next Mar 10 07:46:29 2005 ok
2490 authkey: 5d:a7:dd:70:06:51:32:7e:e7:b6:6d:b3:b5:e5:e0:60:ea:2e:4d:ef
2495 - the date the CRL was installed either in local time or UTC (--utc)
2496 - the number revoked certificates
2497 - the issuer of the CRL
2498 - the URLs of the distribution points where the CRL can be fetched from.
2499 - the dates when the CRL was issued and when the next update
2500 is expected, respectively, expressed either in local time or
2501 UTC (--utc). It is automatically checked if the next update
2502 deadline has passed, resulting either in an "ok" message, a
2503 a "warning" message when strictcrlpolicy=no or a "fatal" message when
2504 strictcrlpolicy=yes.
2505 - the optional authorityKeyIdentifier extension which is a 20 byte SHA-1 hash
2506 over the public key of the issuer who signed the CRL. This extension is
2507 present in version 2 CRLs, only.
2508 - the serial number of the issuer's certificate.
2514 ipsec listocsp [--utc]
2516 lists the contents of the OCSP response cache. The output has the form
2518 issuer: 'C=CH, O=Linux strongSwan, CN=strongSwan Root CA'
2519 uri: 'http://ocsp.strongswan.org:8880'
2520 authname: 13:9d:a0:9e:f4:32:ab:8f:e2:89:56:67:fa:d0:d4:e3:35:86:71:b9
2521 authkey: 5d:a7:dd:70:06:51:32:7e:e7:b6:6d:b3:b5:e5:e0:60:ea:2e:4d:ef
2523 Feb 09 22:56:17 2005, until Feb 09 23:01:17 2005 warning (expires in 4 minutes)
2528 - the distinguished name of the CA handled by the OCSP server
2529 - the http URI of the OCSP server.
2530 - the 20 byte SHA-1 hash of the CA's distinguished name
2531 - the 20 byte SHA-1 hash of the CA's public key
2532 - the serial number of the CA's certificate
2533 - a certificate status list showing
2534 - the time the OCSP status was received
2535 - an optional nextUpdate deadline (if missing the OCSP status will be
2536 onetime with a lifetime of 2 minutes only).
2537 - the serial number of the certificate
2538 - the status of the certificate (good, revoked, unknown)
2543 ipsec listcards [--utc]
2545 lists all smartcard records that are currently in use by Pluto.
2546 The output has the form
2548 Aug 17 16:47:59 2005, #1, count: 6
2549 slot: 0, session closed, logged out, has valid pin
2552 subject: 'C=CH, O=Linux strongSwan, CN=carol@strongswan.org'
2554 with pkcs11keepstate=no and
2556 Aug 17 16:47:59 2005, #1, count: 6
2557 slot: 0, session opened, logged in, has pin pad
2560 subject: 'C=CH, O=Linux strongSwan, CN=carol@strongswan.org'
2562 with pkcs11keepstate=yes and shows
2564 - the date the certificate was read from the smartcard record
2565 - the certificate objects are numbered starting from #1
2566 - the count shows how many connections and secret pin entries point
2567 to the smartcard record
2568 - the PKCS #11 slot number
2569 - the PKCS #11 session state: closed | opened
2570 - the PKCS #11 session login state: logged out | logged in
2571 - the status of the PIN: no pin | valid pin | invalid pin | pin pad
2572 - the ID of the certificate object
2573 - the label of the certificate object
2574 - the subject distinguished name of the certificate
2579 ipsec auto --listall [--utc]
2584 ipsec listpubkeys [--utc]
2585 ipsec listcerts [--utc]
2586 ipsec listcacerts [--utc]
2587 ipsec listaacerts [--utc]
2588 ipsec listocspcerts [--utc]
2589 ipsec listacerts [--utc]
2590 ipsec listgroups [--utc]
2591 ipsec listcainfos [--utc]
2592 ipsec listcrls [--utc]
2593 ipsec listocsp [--utc]
2594 ipsec listcards [--utc]
2597 11. Firewall support functions
2598 --------------------------
2601 11.1 Environment variables in the updown script
2602 ------------------------------------------
2604 strongSwan makes the following environment variables available
2605 in the updown script indicated by the leftupdown option:
2607 +------------------------------------------------------------------+
2608 | Variable Example Comment |
2609 |------------------------------------------------------------------|
2610 | $PLUTO_PEER_ID carol@strongswan.org USER_FQDN (1) |
2611 |------------------------------------------------------------------|
2612 | $PLUTO_PEER_PROTOCOL 17 udp (2) |
2613 |------------------------------------------------------------------|
2614 | $PLUTO_PEER_PORT 68 bootpc (3) |
2615 |------------------------------------------------------------------|
2616 | $PLUTO_PEER_CA C=CH, O=ACME, CN=Sales CA (4) |
2617 |------------------------------------------------------------------|
2618 | $PLUTO_MY_ID @moon.strongswan.org FQDN (1) |
2619 |------------------------------------------------------------------|
2620 | $PLUTO_MY_PROTOCOL 17 udp (2) |
2621 |------------------------------------------------------------------|
2622 | $PLUTO_MY_PORT 67 bootps (3) |
2623 +------------------------------------------------------------------+
2625 (1) $PLUTO_PEER_ID/$PLUTO_MY_ID contain the IDs of the two ends
2626 of an established connection. In our examples these
2627 correspond to the strings defined by rightid and leftid,
2630 (2) $PLUTO_PEER_PROTOCOL/$PLUTO_MY_PROTOCOL contain the protocol
2631 defined by the rightprotoport and leftprotoport options,
2632 respectively. Both variables contain the same protocol value.
2633 The variables take on the value '0' if no protocol has been defined.
2635 (3) $PLUTO_PEER_PORT/$PLUTO_MY_PORT contain the ports defined by
2636 the rightprotoport and leftprotoport options, respectively.
2637 The variables take on the value '0' if no port has been defined.
2639 (4) $PLUTO_PEER_CA contains the distinguished name of the CA that
2640 issued the peer's certificate.
2643 11.2 Automatic insertion and deletion of iptables firewall rules
2644 -----------------------------------------------------------
2646 Starting with strongswan-2.7.0, the default _updown script automatically inserts
2647 and deletes dynamic iptables firewall rules upon the establishment or teardown,
2648 respectively, of an IPsec security association. This new feature is activated
2653 and can be used when the following prerequisites are fulfilled:
2655 - Linux 2.4.x kernel, KLIPS IPsec stack, and arbitrary iptables version.
2656 Filtering of tunneled traffic is based on ipsecN interfaces.
2658 - Linux 2.6.16 kernel or newer, native NETKEY IPsec stack, and
2659 iptables-1.3.5 or newer. Filtering of tunneled traffic is based on
2660 IPsec policy matching rules.
2662 If you define a local client subnet with a netmask larger than /32 behind
2663 the gateway then the automatically inserted FORWARD iptables rules will
2664 not allow to access the internal IP address of the host although it is
2665 part of the client subnet definition. If you want additional INPUT and
2666 OUTPUT iptables rules to be inserted, so that the host itself can be accessed
2667 then add the following line:
2671 The _updown script also features a logging facility which will register the
2672 creation (+) and the expiration (-) of each successfully established VPN
2673 connection in a special syslog file in the following concise and easily
2676 Jul 19 18:58:38 moon vpn:
2677 + @carol.strongswan.org 192.168.0.100 -- 192.168.0.1 == 10.1.0.0/16
2678 Jul 19 22:15:17 moon vpn:
2679 - @carol.strongswan.org 192.168.0.100 -- 192.168.0.1 == 10.1.0.0/16
2682 11.3 Sample Linux 2.6 updown script for iptables < 1.3.5
2683 ---------------------------------------------------
2685 If you are using a Linux 2.6 kernel older than 2.6.16 or an iptables version
2686 older than 1.3.5 then the IPsec policy matching rules will not be available.
2687 In order to make sure that only tunneled packets are accepted, a mark can be
2688 set on incoming ESP packets. This "ESP" mark will be retained on the
2689 decapsulated packet so that iptables rules inserted by the updown script can
2690 check on the presence of this mark. For this purpose the template located in
2692 programs/_updown_espmark
2694 can be used. Store a copy of _updown_espmark e.g. in /etc/ipsec.updown and load
2695 the script with the line
2697 leftupdown=/etc/updown.ipsec.
2699 In addition for the dynamic updown script to work the following static iptables rules
2702 iptables -t mangle -A INPUT -p 50 -j MARK --set-mark 50
2705 12. Authentication with raw RSA public keys
2706 ---------------------------------------
2708 FreeS/WAN, as it is available from www.freeswan.org does public key
2709 authentication with raw RSA public keys that are directly defined in
2712 rightrsasigkey=0sAq4c....
2714 When version 1.x of standard FreeS/WAN receives a certificate request (CR),
2715 it immediately drops the negotiation because it does not know how to answer
2716 the request. As a workaround strongSwan does not send a CR if the RSA
2717 key has been statically loaded using [right/left]rsasigkey. A problem
2718 remains with roadwarriors initiating a connection. Since strongSwan
2719 does not know the identity of the initiating peer in advance, it will always
2720 send a CR, causing the rupture of the IKE negotiation if the peer is a
2721 version 1.x FreeS/WAN host. To circumvent this problem the configuration
2722 parameter 'nocrsend' can be set in the config setup section of /etc/ipsec.conf:
2727 With this entry no certificate request is sent in any connection.
2728 The default setting is nocrsend=no.
2731 13. Authentication with OpenPGP certificates
2732 ----------------------------------------
2734 strongSwan also supports RSA based authentication using OpenPGP
2735 certificates and OpenPGP V3 fingerprints used as an KEY_ID identifier.
2738 13.1 OpenPGP certificates
2739 --------------------
2741 OpenPGP certificates containing RSA public keys can now directly be loaded
2742 in ASCII armored PGP format using the leftcert and rightcert parameters
2747 righcert=peerCert.asc
2749 leftcert=gatewayCert.asc
2751 The peer certificate must be stored locally (the default directory is
2752 /etc/ipsec.d/certs) since currently no trust can be established for
2753 PGP certificates received from a peer via the IKE protocol.
2756 13.2 OpenPGP private keys
2757 --------------------
2759 PGP private keys in unencrypted form can now directly be loaded in ASCII
2760 armored PGP format via an entry in /etc/ipsec.secrets:
2762 : RSA gatewayKey.asc
2764 Existing IDEA-encrypted RSA private keys can be unlocked with GnuPG and
2765 the IDEA extension (see http://www.gnupg.org/gph/en/pgp2x.html) using
2768 gpg --import gatewayCert.asc
2770 gpg --allow-secret-key-import --import gatewayKey.asc
2772 gpg --edit-key <gateway ID>
2773 > passwd #change to empty password
2776 gpg -a --export-secret-key <gateway ID> gatewayKey.asc
2779 13.3 Monitoring functions
2780 --------------------
2782 The command ipsec listcerts shows all loaded PGP certificates
2783 in the following format:
2785 Aug 28 09:51:55 2002, count: 1
2786 fingerprint: 0x1ccfca12d93467ffa9d5093d87a465dc
2787 pubkey: 1024 RSA Key ARHso6uKQ
2788 created: Aug 27 08:51:39 2002
2789 until: --- -- --:--:-- ---- ok (expires never)
2793 - the date the certificate was loaded either in local time or UTC (--utc)
2794 - the V3 fingerprint consisting of the 16 byte MD5 hash of the public key
2795 which is used as an ID of type KEY_ID
2796 - the modulus size of the RSA key in bits
2797 - a keyID consisting of 9 base64 symbols representing the public exponent
2798 and the most significant bits of the modulus
2799 - the creation date of the public key (extracted from the certificate)
2800 - the optional expiration date of the public key (extracted from the
2804 13.4 Suppression of certificate request messages
2805 -------------------------------------------
2807 PGPnet configured to work with OpenPGP certificates aborts the IKE
2808 negotiation when it receives a X.509 certificate. Therefore it is recommended
2809 (mandatory for roadwarrior connections) to set
2817 14. Additional Features
2821 14.1 Authentication and encryption algorithms
2822 ----------------------------------------
2824 strongSwan supports the following suite of encryption and authentication
2825 algorithms for both IKE and ESP payloads.
2827 +------------------------------------------------------------------+
2828 | IKE algorithms (negotiated in Phase 1 Main Mode) |
2829 +------------------------------------------------------------------+
2830 | Encryption algorithms: 3des, aes, serpent, twofish, blowfish |
2831 |------------------------------------------------------------------|
2832 | Hash algorithms: md5, sha, sha2 |
2833 |------------------------------------------------------------------|
2834 | DH groups: 1024, 1536, 2048, 3072, 4096, 6144, 8192 |
2835 +------------------------------------------------------------------+
2837 NOTE: For IKE the SHA-1 algorithm is denoted by "sha"
2839 The cryptographic IKE algorithms listed above are a fixed part of the
2840 strongSwan distribution. Particular algorithms can be added or removed
2841 in the "programs/pluto/alg" directory.
2843 +------------------------------------------------------------------+
2844 | ESP algorithms (negotiated in Phase 2 Quick Mode) |
2845 +------------------------------------------------------------------+
2846 | Encryption algorithms: 3des, aes, serpent, twofish, blowfish |
2847 |------------------------------------------------------------------|
2848 | Hash algorithms: md5, sha1, sha2 |
2849 |------------------------------------------------------------------|
2850 | PFS groups: 1024, 1536, 2048, 3072, 4096, 6144, 8192 |
2851 +------------------------------------------------------------------+
2853 The cryptographic ESP algorithms listed above are a fixed part of the
2854 strongSwan distribution. If your Linux 2.4 or 2.6 kernel includes the
2855 CryptoAPI then additional ESP algorithms can be added or deleted as
2858 The IKE and ESP cryptographic algorithms to be proposed to the peer
2859 as an initiator can be specified on a per connection basis in the form
2863 ike=aes128-sha-modp1536,3des-sha-modp1536
2864 esp=aes128-sha1,3des-sha1
2867 or if you are more paranoid
2871 ike=aes256-sha2_512-modp2048
2875 If the the "ike" and "esp" configuration parameters are missing in
2876 ipsec.conf, then the default settings
2878 ike=3des-md5-modp1536,3des-sha-modp1536,\
2879 3des-md5-modp1024,3des-sha-modp1024
2880 esp=3des-md5,3des-sha1
2882 arre implicitly assumed. The 3DES encryption algorithm and the MD5 and
2883 SHA-1 hash algorithms are hardcoded into strongSwan and cannot be removed.
2885 If Perfect Forward Secrecy (PFS is desired), then a PFS group can be
2886 optionally specified:
2891 pfsgroup=modp2048,modp1536
2894 If the "pfs" parameter is missing then "pfs=yes" is assumed by default.
2895 This means that PFS must be disabled explicitly by setting "pfs=no".
2897 If the "pfsgroup" parameter is missing then the default is
2899 pfsgroup=<Phase1 DH group>
2901 The "ike" and "esp" parameters are used to formulate one or several
2902 transform proposals to the peer if the strongSwan VPN host is the initiator.
2903 Attention! As a responder the first proposal from the peer is accepted that
2904 is supported the by one of the registered algorithms listed by the command
2908 If the responder wants to restrict the allowed cipher suites the '!' flag
2909 can be used to do so. The configuration
2911 conn normal_but_strict
2913 ike=aes128-sha-modp1536,3des-sha-modp1536!
2914 esp=aes128-sha1,3des-sha1!
2917 will only permit the listed algorithms defined above but no other methods
2918 even if they might be supported by the responder.
2924 Currently please refer to README.NAT-Traversal document in the strongSwan
2928 14.3 Dead peer detection
2929 --------------------
2931 strongSwan implements the RFC 3706 Dead Peer Detection (DPD) keep-alive
2932 scheme. If an established IPsec SA has been idle (i.e. without any traffic)
2933 for N seconds (dpddelay=N) then strongSwan side sends a "hello" message
2934 (R_U_THERE) and the peer replies with an acknowledge message (R_U_THERE_ACK).
2935 If no response is received, the R_U_THERE messages are repeated until a DPD
2936 timeout of M seconds (dpdtimeout=M) has elapsed. If still no traffic or
2937 R_U_THERE_ACK packets were received, the peer is declared to be dead and all
2938 SAs belonging to a common Phase 1 SA are deleted.
2940 DPD support is tuneable on a per connection basis by using the dpdaction,
2941 dpddelay and dpdtimeout directives:
2946 leftsubnet=10.1.0.0/16
2951 rightsubnet=10.2.0.0/16
2953 leftsubnet=10.1.0.0/16
2958 In the first example dpdaction=clear activates the DPD mechanism under the
2959 condition that the peer supports RFC 3706. The values dpddelay=30s and
2960 dpdtimeout=120s are assumed by default in the absence of these parameters, so
2961 that during idle periods an R_U_THERE packet is sent every 30 seconds. If no
2962 traffic or a no R_U_THERE_ACK packet is received from the peer within a
2963 120 second time span, the peer will be declared dead and all SAs and associated
2964 eroutes will be cleared.
2966 In the second example R_U_THERE packets are sent every 60 seconds and the
2967 parameter setting dpdaction=hold will put the eroute of the ruptured connection
2968 into a %trap state, so that when new outgoing traffic will occur, the
2969 correspondig connection will be automatically renegotiated as soon as the
2972 It is recommended to use dpdaction=hold for statically defined connections and
2973 dpdaction=clear for dynamic roadwarrior connections. The default value is
2974 dpdaction=none, which disables DPD.
2977 14.4 IKE Mode Config Pull Mode
2978 -------------------------
2980 The IKE Mode Config protocol <draft-ietf-ipsec-isakmp-mode-cfg-04.txt> allows
2981 the dynamic assignment of virtual IP addresses and optional DNS and WINS server
2982 information to IPsec clients. As a default the "Mode Config Pull Mode" is
2983 used where the client actively sends a Mode Config request to the server
2984 in order to obtain a virtual IP. The server answers with a Mode Config reply
2985 message containing the requested information.
2987 Client side configuration (carol):
2991 rightsubnet=10.1.0.0/16
2992 rightid=@moon.strongswan.org
2994 leftsourceip=%modeconfig
2995 leftcert=carolCert.pem
2996 leftid=carol@strongswan.org
2999 Server side configuration (moon):
3003 rightid=carol@strongswan.org
3004 rightsourceip=10.3.0.1
3006 leftsubnet=10.1.0.0/16
3007 leftcert=moonCert.pem
3008 leftid=@moon.strongswan.org
3011 The wildcard %modeconfig or %modecfg used in the leftsourceip parameter of the
3012 client will trigger a Mode Config request. Currently the server will return
3013 the virtual IP address defined by the rightsourceip parameter. In the future
3014 an LDAP-based lookup mechanism will be supported.
3017 14.5 IKE Mode Config Push Mode
3018 -------------------------
3020 Cisco VPN equipment uses the alternative "Mode Config Push Mode" where the
3021 initiating clients waits for the server to push down a virtual address via
3022 a Mode Config set message. The receipt is acknowledged by the client with a
3023 Mode Config ack message.
3025 Mode Config Push Mode is activated by the parameter
3029 as part of the connection definition in ipsec.conf. The default value is
3033 14.6 XAUTH - Extended Authentication
3034 -------------------------------
3036 The XAUTH protocol <draft-beaulieu-ike-xauth-02.txt> allows an extended
3037 client authentication using e.g. a username/password paradigm in addition
3038 to the IKE Main Mode authentication. Thus XAUTH can be used in conjunction
3039 with Pre-Shared Keys (PSK) by defining
3043 or with RSA signatures
3047 in the connection definition, correspondingly. strongSwan can act either as
3048 an XAUTH client with
3052 or as an XAUTH server with
3056 with xauth=client being the default value. strongSwan integrates a default
3057 implementation where the XAUTH user credentials are stored on both the
3058 server and the client in the /etc/ipsec.secrets file, using the syntax
3060 : XAUTH john "rT6q!V2p"
3062 The client must not have more than one XAUTH entry whereas the server can
3063 contain an unlimited number of user credentials in ipsec.secrets.
3065 Either the prompting on the client side or the verification of the user
3066 credentials on the server side can be implemented as a customized XAUTH
3067 dynamic library module. The corresponding library interface is defined
3068 by the pluto/xauth.h header file.
3071 15. Copyright statement and acknowledgements
3072 ----------------------------------------
3075 FreeS/WAN version base system:
3077 Copyright (c) 1999-2004
3078 Henry Spencer, Richard Guy Briggs,
3079 D. Hugh Redelmeier, Sandy Harris, Claudia Schmeing,
3080 Michael Richardson, Angelos D. Keromytis, John Ioannidis,
3082 NAT-Traversal, ipsec starter, Delete SA and Notification messages:
3084 Copyright (c) 2002-2003, Mathieu Lafon
3086 Additional cryptoalgorithms (AES, etc):
3088 Copyright (c) 2002-2003, JuanJo Ciarlante
3090 Dead Peer Detection:
3092 Copyright (c) 2002-2004
3093 Ken Bantoft, JuanJo Ciarlante, Philip Craig,
3094 Pawel Krawczyk, Srinvasan Venkataraman
3096 Porting to Linux 2.6 kernel:
3098 Copyright (c) 2003, Herbert Xu
3100 Dynamic CRL fetching:
3102 Copyright (c) 2002, Stephane Laroche
3104 IKE Mode Config and XAUTH protocol:
3106 Copyright (c) 2001-2002, Colubris Networks
3108 Virtual IP and source routing:
3110 Copyright (c) 2003, Tuomo Soini
3112 Port and protocol selectors for outbound traffic:
3114 Copyright (c) 2002, Stephen J. Bevan
3116 PGPnet-RSA parts of patch:
3118 Copyright (c) 2000, Kai Martius
3120 X.509, OCSP and smartcard functionality:
3122 Copyright (c) 2000, Andreas Hess, Patric Lichtsteiner, Roger Wegmann
3123 Copyright (c) 2001, Marco Bertossa, Andreas Schleiss
3124 Copyright (c) 2002, Uli Galizzi, Ariane Seiler, Mario Strasser
3125 Copyright (c) 2002, Martin Berner, Lukas Suter
3126 Copyright (c) 2003, Christoph Gysin, Simon Zwahlen
3127 Copyright (c) 2004, David Buechi, Michael Meier
3128 Copyright (c) 2000-2005, Andreas Steffen
3130 Zurich University of Applied Sciences in Winterthur, Switzerland
3134 Copyright (c) 2005, Jan Hutter, Martin Willi
3135 Copyright (c) 2005-2007, Andreas Steffen
3137 University of Applied Sciences in Rapperswil, Switzerland
3139 This program is free software; you can redistribute it and/or modify
3140 it under the terms of the GNU General Public License as published by
3141 the Free Software Foundation; either version 2 of the License, or
3142 (at your option) any later version. See http://www.fsf.org/copyleft/gpl.txt.
3144 This program is distributed in the hope that it will be useful, but
3145 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
3146 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
3148 -----------------------------------------------------------------------------
3150 This file is RCSID $Id: README,v 1.38 2007/01/14 18:16:51 as Exp $