This is an ancient problem that I dont think ever is going to get fixed in the EMU, the emulator binds to INET_ANY rather than a specific interface on your MASQ machine. Theres a code fix that solves the problem for most of us on Linux (I haven't used it on a windows box since version 2.something), but it works fine on mulithomed Linux boxes. Personally. I think there should be an option to pass into the emulator (say in addon.ini, or loginserver.ini) where you can specify which interface to bind to.
The work around is this.
1) Go get a dynamic dns name (
www.dyndns.org is a good one), get one of there automatic ip updaters while you are at it, then your dns entry will get updated anytime your ip changes.
2) In your internal machines /windows/host (/windows/drivers/etc/host, your location may vary depending on your version of windows), map your INTERNAL ip address to the dns name you created. For instance, something like this
192.168.0.1 firewall.dyndns.org
Reboot after this to make sure.. Then try pinging your internal box dns name and verify you see the internal ip rather than the external.
for those that dont know how to ping, you should if you know how to set up network sharing so I'll leave that as an exercise for the reader to figure out.
3) When you start zones on your firewall box, start them with
zone . firewall.dyndns.org 7995 firewall.dyndns.org
This work around works for some people, not for others. There is a code fix posted in the Linux forum that should work too if you know how to recompile.