Some questions:
1) Are you connecting via an external router? (I'm assuming a broadband connection here)
2) Is your machine set up as a DHCP client, or are you using a static IP?
3) Finally (and I'm just throwing this one out there) if you ARE using DHCP, is it possible your lease is set really, really low? I'm no expert on this by any means, but I've had the same thing happen to me before when I had my lease expiration value on my router set too low... But 10 minutes seems a little extreme
