I have a 2851 router. Please see the attached configuration file. In attempting to get it to work at all, I have tried both IOS 12.4(15)T3 (ED) AdvancedIPServices and 12.4(18) (LD) IPBase. I have the same problem with both. I have created a very basic config, but can't get routing to work. The configuration of the network is as follows: <my PC> - <2851> - <telco managed router> - <internet>. The IP address of my PC is 10.30.10.55/24. The "internal" address of the 2851 is 10.30.10.5/24, while the "external" address is close to 126.96.36.199/28. The 2851-facing side of the Telco managed router is close to 188.8.131.52/28.
When logged onto the console of the 2851, I can successfully ping my local PC, both interfaces on the 2851, the 184.108.40.206 address on the Telco router and other addresses out on the Internet. However, from my local PC, I can only ping the two interfaces on the 2851 (and other devices on my local network), not the telco interface (220.127.116.11), nor other addresses on the Internet. I am not able to do anything else over the Internet (e.g. browse a website) either.
This seems like it should be the most basic routing possible, but I am simply unable to get it to work. Am I missing something?