Sometimes my netbook (Dell Mini 10v with Broadcom bcm4322 wireless adapter, Ubuntu 12.04.2 LTS) gets into a state where it can see wireless connections but not connect to them.
Rebooting always fixes this, but is a pain in the neck.
sudo service network-manager restart
works too, but not always.
I suspect a problem somewhere in the network stack, probably driver-related, but I've no idea how to find out what it is, and the fault is too intermittent for blind debugging anyway.
Is there any way to force a reset of the entire network stack without having to do a full reboot?
Several different commands is fine. I can script.
Failing that, is there a detailed guide to working out what the problem actually is?