I have users who need to run an IPSec VPN from a client through my RedHat Linux-based router, which is running a Shorewall firewall. The firewall is doing NAT. I have a single public IP address.
Linksys routers have an option called "IPSec Passthrough" which I have found allows this VPN traffic to pass through. How can I configure the Shorewall firewall to allow the IPSec traffic to just "pass through?" I have opened up all the necessary ports, but no luck.
Anyone have experience with this?