Cisco IP forwading challenge on a cisco router

Question

I have been trying to setup a cisco gateway router that has a Mail server behind it. The challenge has been that the static nat entries are no effective or perhaps do not work. Has anyone done this in areal life environment? testing for open ports shows that all the static NAT ports are closed .Please share

Answer 1

I Actually found out that the problem was the gateway on the mail server that was still pointing to the old ISP instead of the router connecting to the new ISP.