Also see: FireBrick Road Warrior strongSwan

Linux (CentOS Openswan) Example Using IKE2 and Preshared keys

yum install openswan

(strongswan is much nicer, but not in yum on centos5. On centos6, use strongswan)

In /etc/ipsec.conf uncomment

include /etc/ipsec.d/*.conf

Put following two files in /etc/ipsec.d/ :

file: myFireBrick.conf:

 conn myFireBrick
        authby=secret
        auto=start
        ikev2=insist
        left=CentOS.IP.Address
        leftid=CentOS.IP.Address
        leftsubnet=CentOS.IP.Address/32
        right=FireBrick.IP.Address
        rightid=FireBrick.IP.Address
        rightsubnet=FireBrick.LAN.SUBNET/24

file: myFireBrick.secrets:

CentOS.IP.Address FireBrick.IP.Address : PSK "YourSecretHere"

chkconfig ipsec on
service ipsec start

Put the following in the FB at the other end:

 <connection name="IPSec" peer-ips="CentOS.IP.Address" auth-method="Secret" secret="YourSecretHere" local-ip="FireBrick.LAN.IP.Address/24" routes="CentOS.IP.Address" log="default"/>

strongSwan

file: /etc/ipsec.conf

 conn myFireBrick
       authby=secret
       auto=start
       left=strongSwan.IP
       leftid=strongSwan.IP
       leftsubnet=strongSwan.IP
       right=FireBrick.IP
       rightid=FireBrick.IP
       rightsubnet=FireBrick.LAN.IP.Address/24
       lifetime=2m

file: /etc/ipsec.secrets

 strongSwan.IP FireBrick.IP : PSK "YourSecretHere"

Put the following in the FB at the other end:

 <connection name="IPSecTostrongSwan" peer-ips="strongSwan.IP" auth-method="Secret" secret="YourSecretHere" local-ip="FireBrick.LAN.IP.Address/24" routes="strongSwan.IP" log="default"/>