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.

for support of the old-style klips ipsecx network interfaces a custom kernel module is needed.

this package contains source code for the openswan ipsec kernel module, which can be used with tools like module-assistant or kernel-package for manual building of local kernel images.

kernel versions >= 2.6.23 no longer need to be patched to provide nat traversal support for klips.