Comment 16 for bug 277634

I had a related problem which has been similarly reported elsewhere

Running Jaunty on a T61 with Intel 4965 AGN. Wireless worked fine on Intrepid, but has had problems since upgrading to Jaunty. A fresh Jaunty install did not fix (not 100% fresh, migrated my home folder)

Wireless would always successfully connect upon startup, but after some time (varying from minutes - usually - to sometimes hours), the internet and network devices would become suddenly unavailable, although network manager showed the network as still being connected. Seems to occur with both networkmanager and wicd.

After being unable to find a reliable way to cause the problem, I read Augusten's post about removing motd, and followed that using Synaptic. So far no disconnects (a day), which seems to me to be a minor miracle.