@johnpoz:
ISA is a proxy.. Using NAT is not the same thing as a proxy.. You could install one of the packages that allows for reverse proxy - one of those might have the setting your ISA did.
The squid3 reverse proxy seems to rewrite the source address like ISA so that might be the solution. I will look into that.
But it seems to only apply to http-trafic. If I wanted to use port 22 for SSH it might not help?
Why don't you just put both wan connections on the pfsense box as how to solve this?
Or have the webserver use psfsense as its default gateway if that is where the traffic comes in. If you go out the other router you have a asynchronous routing issue.
Having pfSense handle all WAN addresses is my end goal and will probably solve my problems. For the time being however I am stuck with the current multi-WAN.
(we have 10 VOIP phones that connect directly to an external VOIP provider. This works fine with our old and simple WRT54G router but fails with more modern routers. It makes me very hesitant to switch them to pfSense. I have yet to try the siproxd package)
Am I correct that the 'reply-to' feature of the firewall only applies to the multi-WAN where pfSense handles all addresses?