basic routing problem--ISP uses DHCP

[jeremy.lebeau]

I have a simple problem that I am drawing a blank on. I have a 1812 router and Fa1 is connected to a cable modem for the external connection. The ISP uses DHCP, and I get an IP address successfully, and I can ping an external address successfully--until I specify that it is coming from the internal address (192.168.30.1/Vlan1).

I know it is something simple, but I am drawing a blank. I added the current config below.

[wedwardsvt]

It doesn't look like you are using Network Address Translation. The IP's that you're using on your internal network are not publicly routable (they're RFC 1918 addresses). Check out the following link for an example:

http://www.cisco.com/warp/public/556/12.html