Openswan is an ipsec based vpn solution for the linux kernel. it can use the native ipsec stack as well as the klips kernel module. both ikev1 and ikev2 protocols are supported.

the openswan ike daemon is named pluto. it was inherited from the frees/wan project, but provides improved x.509 certificate support and other features.

in order to use the klips ipsec code instead of the native version, you will need to either install openswan-modules-source and build the appropriate module for your kernel or use openswan-modules-dkms which automates this task.