I also have an issue with my NAT connection, I have done the needful according to the configuration above, but I cannot ping the internet.
Brief explanation, we were given a pool of private IP addresses by ISP which has already been NATted on their own network. Is it advisable to NAT to these addresses to prevent ambiguity in configuration?
After I NAT into these address pool, I can ping the modem from my client PC and can see the translations using the "sh ip nat trans" but I cannot ping any external internet address.

Pls advice.