The file ipsec.secrets holds a table of secrets, used by the FreeS/WAN Internet Key Exchange daemon ipsec_pluto to authenticate other hosts. There are two kinds of secrets: preshared secrets and RSA private keys. This example shows the use of a preshared secret, using the identifier "PSK". Preshared secrets require that both systems have the identical secret configured. If both the host and the VPN peer appear in the index list (as shown below), the same passphrase will be used for both communication directions.
# start /etc/ipsec.secrets Linux FreeSwan IPSEC shared passphrase file
128.12.2.10 128.12.1.155 PSK "dobsekred"
# end /etc/ipsec.secrets Linux FreeSwan IPSEC shared passphrase file