I have been searching for a way to enable multiple ipsec based vpn clients to be able to connect to their various vpn termination points from behind iptables nat.
In our network environment, we will have many different types of vpn clients connecting back to their home offices at any given time.

We can make this work behind a Cisco Pix and even behind a Linksys router, but we want to be able to run a captive portal that requires the user to login (radius). So far I have tested monowall (very nice, but no multiple vpn), chillispot (same issue) and a few others.

Has anyone been successful in making this work?
Our server base is CentOS (redhat clone)

Thanks

any takers?