Horde modifying the server address - no good behind firewall

[Dave Stubbs]

Hello,

I am running IMP behind a firewall.

My Linux server with IMP on it is (for the sake of argument) penguin.inside.intranet

My firewall / reverseproxy is (for the sake of argument) penguin.outside.com

So when I'm out there and open a browser (any browser - I checked a few just to make sure) and open http://penguin.outside.com/horde the traffic gets piped through the reverse proxy to my IMP server and the problems start.  My browser suddenly starts to try loading http://penguin.inside.intranet/horde which is (of course) not reachable from the outside world.  I browsed the docs and the setup files but cannot find anything that looks like it will disable this remap of the server address.  It does the same thing for anything that uses horde.

Anyone know how to stop this from happening?

Dave....