when I call asterisk from my lan with a not registered softphone, the call gets processed!
so I enabled debugging and made a call via the googletalk sip gateway: no signs of it in the log,
but I can see the invite in tcpdump: looks like a firewall problem but then again I can receive calls via my voip provider,
I opened up the firewall to be sure, and it works…
sorry guys and girls, it was no asterisk problem
thanks for looking