how to configure a FreeBSD firewall to pass IPSec?

[Crist J. Clark]

On Wed, Apr 30, 2003 at 04:53:48PM -0400, Guy Middleton wrote:
> On Wed, Apr 30, 2003 at 02:50:44PM -0400, Lowell Gilbert wrote:
> > Guy Middleton <guy at obstruction.com> writes:
> > 
> > > I have a FreeBSD box acting as a firewall and NAT gateway
> > > 
> > > I would like to set it up to transparently pass IPSec packets -- I have
> > > an IPSec VPN client running on another machine, connecting to a remote network.
> > > 
> > > Is there a way to do this?  I can't find any hints in the man pages.
> > 
> > It's impossible.  IPSEC can't be passed through a NAT.
> > 
> > The best you could do would be to terminate the tunnel on the gateway itself.
> 
> Ok, now I'm confused.  The same client (Cisco VPN 3.5 on Windows) works
> through a LinkSys router / NAT gateway (a BEFSR81) at a different location.
> The LinkSys even has a friendly little check-box to allow IPSec pass-through.
> 
> I would like the FreeBSD gateway to work the same way as the LinkSys.

Have you tried it? A Cisco VPN client worked fine for me the first
time I tried. Of course, we are using UDP encapsulation. And LinkSys
routers have actually been the only thing we've found that manage to
break the Cisco clients (the LinkSys "pass-through" was actually
breaking it). Funny.
-- 
Crist J. Clark                     |     cjclark at alum.mit.edu
                                   |     cjclark at jhu.edu
http://people.freebsd.org/~cjc/    |     cjc at freebsd.org