[Kernel_Killer]

Peter Matulis at papamike dot ca wrote this article to cover just about anything and everything about OpenBSD's IPsec. It goes into the depths of the protocols, and how to implement a simple IPsec solution, a ISAKMPD peer-to-peer solution, a ISAMPD net-to-net solution, and even a Windows-to-ISAKMPD solution. If there was anything you were wondering about OpenBSD's IPsec, this would be a great palce to start.

Implementing IPsec on OpenBSD (http://www.papamike.ca/tutorials/pub/obsd_ipsec.html)