On my parent's (XP) computer when they first try to access a website after booting, they are typically redirected to the ISPs authetication page at an IP address like 10.10.xxx.xxx, and after verifying their credentials they can access the internet.

I installed quantal using WUBI on that box. Mimicking my parents internet configuration I provided the IP, Gateway, Subnet Mask by clicking on the network icon on the top right, selecting IPV4 in the manual mode.

This works, but not consistently.

If I boot into UBUNTU after a while, the internet connection does not work, I cannot even access the authentication page. However if I then boot into XP, I can access the authentication page, and if I immidiately reboot into ubuntu after providing my credentials, I can access the internet in UBUNTU.

I do not understand what is happening. I am interesting in logging into Ubuntu directly and being able to access the internet.