Dreamcast online problem

[soundtest]

If you're using WinXP I think you can do this to find the DNS servers you're using:

Start -> Settings -> Control Panel -> Network and Internet Connections (skip this if you're in Classic view) -> Network Connections

Double click on Local Area Connection, click the Support tab and click details. It should list 2 DNS addresses.

Who is your Cable ISP? If your IP address is not static the DNS addresses might be obtained dynamically/automatically too...