Company B has a telnet service running inside their network at10.110.0.202:23. They setup a rule in their boundary PIX that allows my local address 172.16.2.114 to access this service. Their routing from the PIX & beyond is a black box. It currently works correctly.
I want to access this telnet service from more than 1 workstation on my LAN (Company B doesn't care if I do this, but currently their config only allows172.16.2.114). So, rather that go through their tiresome IT hierarchy to get this changed, I simply removed host 172.16.2.114 from my LAN and configured my router to inside source NAT packets destined for 10.110.0.202:23 as 172.16.2.114. But unfortunately this does not work (I receive no response from their telnet service).
After some troubleshooting (from my end only, they are reluctant to assist), the only thing I can figure is that their PIX router must realize that I am implementing NAT, and dropping the packet(s) accordingly. "It works" if I assign 172.16.2.114 to a workstation (connection successful), but it does "not work" if workstation 192.168.1.23 gets source NATed to 172.16.2.114 (my router never receives any response packets from 10.110.0.202 at all). I guess the PIX firewalls when I NAT.
Without knowing their PIX config, is it [probably] correct and/or possible that it realizes I am NATed and is therefor dropping the packets, or should it not be able to tell the difference (meaning I am doing something wrong)?