After port forwarding, how do I access internal services like outside?

[utoyo]

Just set up port forwarding on a cisco 1711, but I can't access internal resources like outside w/o getting a login to the router. For example, if I try to go to

http://www.somewhere.com,

from outside the network then I get the webpage, but if I try to do it on an internal machine I get the login prompt to the router.

Where can I change this behavior?

Thanks in Advance.