I have a pretty standard NAT setup for a company with a small Cisco 871 WAN router:
int E0, IP=xxx.xx.xx.xx, ip nat outside
int Vlan1, IP=192.168.1.1 ip nat inside
one port forwarding rule:
ip nat inside source static tcp 192.168.1.20 110 xxx.xx.xx.xx 110 extendable
People have laptops set up with an email application that has the xxx.xx.xx.xx public IP hard-coded in it. It works fine outside "on the Internet", but when they bring their laptops into work, it doesn't work. Now, obviously, one solution is to change the hard-coding of the app to go to the Vlan1 IP of 192.168.1.20 instead the outside public IP of xxx.xx.xx.xx
But is there a way to do this with "ip nat" statements?
I tried an "ip nat outside static 192.168.1.20 xxx.xx.xx.xx" but that didn't work.