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allow ipsec passthrough using shorwall firewall

quadquay asked
Last Modified: 2013-11-16
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?
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The Shorewall documentation (http://man.chinaunix.net/network/shorewall-docs-html-3.0.8/) seems like it has a section addressing your question.



The server I'm trying to reach doesn't allow NAT-T or UDP encapsulation.  Any other ideas?
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My final solution was to use a second public IP address and do one-to-one NAT from the public IP to the workstation running the IPSec client.

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