surely your cablemodem has an intgrated dhcp. (meaning it distributes ip adresses to client pc's). But...
With most of cablemodem companies you MUST use their proxy server.
So you may have to alter the proxy settings in Konqueror or netscape (mozilla) to get your webpages. (especially if you're working trough a router).
You can do this in 2 ways :
-directly enter the proxy settings in your application (konq. / mozilla)
in this case you'd better enter also in the exeption list the last part of the adress as an exeption)
-or use a pac file location

greetzzzzz...