Ineternet through a router only?

I had my internet all working before my brother came over with his laptop. (Mediacom Cable Internet) We set up the router(D-link DI-604) and everything works through it but if I go straight from my cable internet to my computer it won't give me the correct ip address and it comes up as a limited or no connectivity error. I have the ip set to obtain automatically.

I wouldn't care but there is some issue with steam through this router and it slows everything down so I would rather not use it.

Any ideas would be helpful.

It sounds like there is no DHCP server on the other end of the cable line, or this modem has a built in router, and expect you to have a static IP address. Check to see if this modem infact has a router in it. I know my DSL one does.

There isn't a router in the modem. It's just a modem. There would have to be a DHCP on the other end wouldn't there?

I would imagine there should be. Especially if you don't have static IPs. Hm. did you call your cable company? Tell them you can't connect and don't mention the router.

Have you tried resetting your cable modem after you connect it directly to your computer? I remember having problems in the past switching from a connection through a router to a connection directly to the cable modem. Resetting the cable modem fixed it for me.

Well, now don't I feel retarded. Resetting the modem worked.

Thanks for the help Cheator, I think you and I were just thinking to hard.

And thanks for the obvious Buckeye.