FreeBSD was not tested, but configuration should be similar to NetBSD as both use Kame IPv6 and IPsec. The IPsec implementation of the upcoming Linux 2.6 release provides a Kame compatible userland-interface, so the here provided examples for NetBSD should be suitable as well.
Given configuration files will be minimal and focused on an interoperable setup. Therefor a very simple LAN of severel boxes is used and only host-to-host connections will be covered.
Extending the following examples to reallife VPN configurations, e.g. host-to-network or network-to-network, will not affect the basic setup concerning interoperability.
In the following examples all IPsec clients and gateways use the following main mode configuration:
These quick mode parameters are used:
For all systems I present configuration for two typical applications:
We will use X509 certificates to authenticate the quick mode exchanges. Therefore we need the following items:
In the examples, the file cacert.pem contains the PEM-encoded CA certificate. The certificates of the gateways and clients are called fqdn.pem and the private key fqdn.priv. By the way, make sure to set the permission of the privte keys to 0400.
How these certificates and keys are generated is described in this document.
The sample network consists of the following machines (some of them are actually VMware guests):
Openbsd1, linux1, netbsd1 and win2000 are gateways and are connected to each other using an IPsec tunnel. The roadwarrior[1234].as10.net machines obtain arbitrary dynamic IP adresses and also connect to the gateways using IPsec tunnels.
# ls /etc/isakmpd ca/ crls/ isakmpd.policy private/ certs/ isakmpd.conf keynote/The CA certificate is stored in ca/, the machines certificate in certs/ and the private key in private/:
# ls -l ca/ certs/ private/ ca/: total 4 -r--r--r-- 1 root wheel 1379 Jun 16 21:21 cacert.pem certs/: total 10 -r--r--r-- 1 root wheel 4312 Jun 16 21:21 openbsd1.as10.net.pem private/: total 4 -r-------- 1 root wheel 1679 Jun 16 21:21 openbsd1.as10.net.privNote the permissions for the private key!
There are two configuration files for isakmpd: isakmpd.conf and isakmpd.policy. isakmpd.conf is the main configuartion file and isakmpd.policy defines rules for authenticating quick mode exchanges.
# Incoming phase 1 negotiations are multiplexed on the source IP address [Phase 1] Default= ISAKMP-peer-void # These connections are walked over after config file parsing and told # to the application layer so that it will inform us when traffic wants to # pass over them. This means we can do on-demand keying. [Phase 2] Connections=IPsec-openbsd1-gate # The peers [ISAKMP-peer-void] Phase= 1 Transport= udp Local-address= 192.168.3.19 Configuration= Default-main-mode ID= openbsd1-ID [ISAKMP-peer-linux1] Phase= 1 Transport= udp Local-address= 192.168.3.19 Address= 192.168.3.11 Configuration= Default-main-mode ID= openbsd1-ID Remote-ID= gate-ID [ISAKMP-peer-netbsd1] Phase= 1 Transport= udp Local-address= 192.168.3.19 Address= 192.168.3.21 Configuration= Default-main-mode ID= openbsd1-ID Remote-ID= netbsd1-ID [ISAKMP-peer-win2000] Phase= 1 Transport= udp Local-address= 192.168.3.19 Address= 192.168.3.64 Configuration= Default-main-mode ID= openbsd1-ID Remote-ID= win2000-ID [openbsd1-ID] ID-type= FQDN Name= openbsd1.as10.net [linux1-ID] ID-type= FQDN Name= linux1.as10.net [netbsd1-ID] ID-type= FQDN Name= netbsd1.as10.net [win2000-ID] ID-type= FQDN Name= win2000.as10.net # The connections [IPsec-openbsd1-void] Phase= 2 Configuration= Default-quick-mode Local-ID= Net-default Remote-ID= Net-remote [IPsec-openbsd1-linux1] Phase= 2 ISAKMP-peer= ISAKMP-peer-gate Configuration= Default-quick-mode Local-ID= Host-openbsd1 Remote-ID= Host-linux1 [IPsec-openbsd1-netbsd1] Phase= 2 ISAKMP-peer= ISAKMP-peer-gate Configuration= Default-quick-mode Local-ID= Host-openbsd1 Remote-ID= Host-netbsd1 [IPsec-openbsd1-win2000] Phase= 2 ISAKMP-peer= ISAKMP-peer-gate Configuration= Default-quick-mode Local-ID= Host-openbsd1 Remote-ID= Host-win2000 # The networks [Net-default] ID-type= IPV4_ADDR Address= 0.0.0.0 [Net-remote] ID-type= IPV4_ADDR Address= 0.0.0.0 [Host-openbsd1] ID-type= IPV4_ADDR Address= 192.168.3.19 [Host-linux1] ID-type= IPV4_ADDR Address= 192.168.3.11 [Host-netbsd1] ID-type= IPV4_ADDR Address= 192.168.3.21 [Host-win2000] ID-type= IPV4_ADDR Address= 192.168.3.64 # Main mode descriptions [Default-main-mode] EXCHANGE_TYPE= ID_PROT Transforms= 3DES-SHA,3DES-MD5 # Quick mode descriptions [Default-quick-mode] EXCHANGE_TYPE= QUICK_MODE Suites= QM-ESP-AES-SHA-PFS-SUITE,QM-ESP-AES-SHA-PFS-SUITE # ##################################################################### [General] Policy-File= /etc/isakmpd/isakmpd.policy Retransmits= 3 Exchange-max-time= 120 Listen-on= 192.168.3.19 Renegotiate-on-HUP= yes # KeyNote credential storage [KeyNote] Credential-directory=/etc/isakmpd/keynote/ # Certificates stored in PEM format [X509-certificates] CA-directory= /etc/isakmpd/ca/ Cert-directory= /etc/isakmpd/certs/ Private-key= /etc/isakmpd/private/openbsd1.as10.net.priv # Main mode transforms ###################### # 3DES [3DES-SHA] ENCRYPTION_ALGORITHM= 3DES_CBC HASH_ALGORITHM= SHA AUTHENTICATION_METHOD= RSA_SIG GROUP_DESCRIPTION= MODP_1024 Life= LIFE_3600_SECS [3DES-MD5] ENCRYPTION_ALGORITHM= 3DES_CBC HASH_ALGORITHM= MD5 AUTHENTICATION_METHOD= RSA_SIG GROUP_DESCRIPTION= MODP_1024 Life= LIFE_3600_SECS # Quick mode protection suites ############################## # AES [QM-ESP-AES-SHA-PFS-SUITE] Protocols= QM-ESP-AES-SHA-PFS [QM-ESP-AES-MD5-PFS-SUITE] Protocols= QM-ESP-AES-MD5-PFS # Quick mode protocols ###################### # AES [QM-ESP-AES-SHA-PFS] PROTOCOL_ID= IPSEC_ESP Transforms= QM-ESP-AES-SHA-PFS-XF [QM-ESP-AES-MD5-PFS] PROTOCOL_ID= IPSEC_ESP Transforms= QM-ESP-AES-MD5-PFS-XF # Quick mode transforms ####################### # AES [QM-ESP-AES-SHA-PFS-XF] TRANSFORM_ID= AES ENCAPSULATION_MODE= TUNNEL AUTHENTICATION_ALGORITHM=HMAC_SHA GROUP_DESCRIPTION= MODP_1024 Life= LIFE_600_SECS [QM-ESP-AES-SHA-MD5-XF] TRANSFORM_ID= AES ENCAPSULATION_MODE= TUNNEL AUTHENTICATION_ALGORITHM=HMAC_MD5 GROUP_DESCRIPTION= MODP_1024 Life= LIFE_600_SECS # Lifetimes ########### [LIFE_600_SECS] LIFE_TYPE= SECONDS LIFE_DURATION= 600,450:720 [LIFE_3600_SECS] LIFE_TYPE= SECONDS LIFE_DURATION= 3600,1800:7200
# /etc/ipsec.conf - FreeS/WAN IPsec configuration file # basic configuration config setup interfaces=%defaultroute klipsdebug=none plutodebug=none plutoload=%search plutostart=%search uniqueids=yes # defaults for subsequent connection descriptions conn %default keyingtries=0 ikelifetime=1h rekeymargin=2m keylife=10m disablearrivalcheck=no esp=aes128-sha1 authby=rsasig left=192.168.3.11 leftnexthop=%defaultroute leftcert=linux1.as10.net.pem leftid=@linux1.as10.net rightrsasigkey=%cert auto=start conn linux1-void auto=add right=@any conn linux1-openbsd1 auto=start right=192.168.3.19 rightid=@openbsd1.as10.net conn linux1-netbsd1 auto=start right=192.168.3.21 rightid=@netbsd1.as10.net conn linux1-win2000 auto=start right=192.168.3.64 rightid=@win2000.as10.net/etc/ipsec.secrets
: RSA linux1.as10.net.privFiles in /etc
# ls /etc/ipsec.d cacerts/ crls/ linux1.as10.net.pem private/ # ls /etc/ipsec.d/cacerts cacert.pem # ls -l /etc/ipsec.d/private/ total 4 -r-------- 1 root root 1679 Jun 22 20:26 linux1.as10.net.priv
options IPSEC # IP security options IPSEC_ESP # IP security (encryption part; define w/IPSEC)Then recompile and after a reboot IPsec is enabled.
With NetBSD/KAME the IPsec SAs are configured using the setkey (8) command. As soon as some IP packets are bound to use these SAs, the ISAKMP/IKE daemon called racoon (8) is notified and the keys for IPsec SAs are negotiated.
To install IPsec SAs and start the racoon (8) automatically on system startup add these to lines to /etc/rc.conf:
# tail -2 /etc/rc.conf ipsec=yes racoon=YESThe file /etc/ipsec.conf contains the arguments for setkey (8):
# netbsd1.as10.net - openbsd1.as10.net spdadd 172.16.89.0/24 192.168.233.0/24 any -P out ipsec esp/tunnel/192.168.3.21-192.168.3.19/require; spdadd 192.168.233.0/24 172.16.89.0/24 any -P in ipsec esp/tunnel/192.168.3.19-192.168.3.21/require; # netbsd1.as10.net - linux1.as10.net spdadd 172.16.89.0/24 172.16.235.0/24 any -P out ipsec esp/tunnel/192.168.3.21-192.168.3.11/require; spdadd 172.16.235.0/24 172.16.89.0/24 any -P in ipsec esp/tunnel/192.168.3.11-192.168.3.21/require;As IPsec SAs are unidirectional we have to define two SAs for each tunnel: One outgoing and one incoming SA. spdadd adds a new SA to the kernel.
Let's have a closer look on the tunnel between netbsd1 and openbsd1: The first two arguments for spdadd are the source and destination addresses of IP datagrams which shall use this SA. The private networks attached to netbsd1 and openbsd1 are 172.16.89.0/24 and 192.168.233.0/24 respectively. Thus on netbsd1 the source address for the outgoing SA is 172.16.89.0/24 and the destination address is 192.168.233.0/24. The third argument "any" tells the kernel to send any protocol type through this SA. For example we could say "tcp" to send only TCP segments through this SA.
With "-P" we define the policy for this SA: "out ipsec" tells the kernel that this is an outgoing SA and "in ipsec" an incoming SA. The last -- rather long argument -- describes the IPsec protocol to be applied for this policy. For the outgoing SA this is ESP in tunnel mode between netbsd1 and openbsd1. The "require" keyword tells the kernel to drop any packet, which matches this SA but is not protected by IPsec. This is important! If we would use the keyword "use", the kernel would also accept non-protected packets. For our VPN-scenario this is not acceptable.
Before we can use racoon (8) we have to prepare our certificates and the private key. All these items are stored in the directory /etc/openssl/certs:
# ls /etc/openssl certs/ misc/ private/ # ls -l /etc/openssl/certs total 9 lrwxr-xr-x 1 root wheel 10 Aug 13 01:38 938565a9.0 -> cacert.pem -r--r--r-- 1 root wheel 1379 Aug 13 01:37 cacert.pem -r--r--r-- 1 root wheel 4305 Aug 13 01:36 netbsd1.as10.net.pem -r-------- 1 root wheel 1679 Aug 13 01:36 netbsd1.as10.net.privAgain, make sure to keep the private key readable only for root! racoon (8) uses the hash of the CA certificate to identify the file which contains this certificate and expects this file to be named "hashvalue.0". Use this command to create an appropriately named link to cacert.pem:
ln -sf cacert.pem `openssl x509 -noout -hash -infile cacert.pem`.0
The configuration file for racoon is /etc/racoon/racoon.conf:
path certificate "/etc/openssl/certs" ;
log notify;
# phase 1 proposals (for IKE SA)
# openbsd1.as10.net
remote 192.168.3.19
{
exchange_mode main;
my_identifier fqdn "netbsd1.as10.net";
peers_identifier fqdn "openbsd1.as10.net";
certificate_type x509 "netbsd1.as10.net.pem" "netbsd1.as10.net.priv" ;
lifetime time 1 hour ; # sec,min,hour
passive off ;
proposal {
encryption_algorithm 3des;
hash_algorithm sha1;
authentication_method rsasig ;
dh_group 2 ;
}
proposal {
encryption_algorithm 3des;
hash_algorithm md5;
authentication_method rsasig ;
dh_group 2 ;
}
proposal_check obey;
}
# linux1.as10.net
remote 192.168.3.11
{
exchange_mode main;
my_identifier fqdn "netbsd1.as10.net";
peers_identifier fqdn "linux1.as10.net";
certificate_type x509 "netbsd1.as10.net.pem" "netbsd1.as10.net.priv" ;
lifetime time 1 hour ; # sec,min,hour
passive off ;
proposal {
encryption_algorithm 3des;
hash_algorithm sha1;
authentication_method rsasig ;
dh_group 2 ;
}
proposal {
encryption_algorithm 3des;
hash_algorithm md5;
authentication_method rsasig ;
dh_group 2 ;
}
proposal_check obey;
}
# from the void
remote anonymous
{
exchange_mode main;
my_identifier fqdn "netbsd1.as10.net";
certificate_type x509 "netbsd1.as10.net.pem" "netbsd1.as10.net.priv" ;
lifetime time 1 hour ; # sec,min,hour
passive on;
generate_policy on;
proposal {
encryption_algorithm 3des;
hash_algorithm sha1;
authentication_method rsasig ;
dh_group 2 ;
}
proposal {
encryption_algorithm 3des;
hash_algorithm md5;
authentication_method rsasig ;
dh_group 2 ;
}
proposal_check obey;
}
# phase 2 proposal (for IPsec SA).
# quick mode description for all connections
sainfo anonymous
{
pfs_group 2;
lifetime time 10 min ;
encryption_algorithm rijndael;
authentication_algorithm hmac_sha1, hmac_md5 ;
compression_algorithm deflate ;
}