I have an Asterisk server on a public IP address. I am using the N900 SIP client to connect as an extension. Everything works over WiFi but registration drops after a couple of minutes over tmobile 3g, i.e. asterisk doesn't see the extension as online anymore and calls go to voicemail.


If I get on the phone as root and put the phone in a continuous ping to anywhere on the internet, registration stays on for like 20 minutes before dropping.

Any ideas?