HP-UX IPFilter Version A.03.05.14 Administrator's Guide

HP-UX IPFilter and IPSec
IPSec Gateways
Chapter 9136
IPSec Gateways
You can configure IPSec to encrypt and authenticate traffic to a gateway
between two end hosts. A configuration that encrypts IPSec packets to a
gateway is called an IPSec tunnel.
IPFilter can coexist with IPSec tunnels without conflict. However, you
must configure IPFilter to allow IPSec traffic with the gateway instead of
the end node. The IPFilter rules for the UDP/500 and protocol 50/51
traffic must be passed to and from the gateway IP address rather than
the end node IP address.