Comment 16 for bug 97591

You can keep your Network Manager as is, just do the following:

1)determine your IP using ifconfig (ifconfig lists all active and inactive connections - so you choose the IP your active internet connection has)

2) go to pidgin->tools->preferences->network
uncheck the "Autodetect IP address" field and set the IP you just noted down in the Public IP.

That solved the problem for me (however, if you get a different IP address everytime you connect to the internet, u r still in a mess)