That leaves Peer Guardian the culprit.. Just open it and configure it..

As far as Netgear DG834 is concerned, it has many models.. (e.g DG834g, DG83Gt)... Confirm if yours is the simple one..

Check that too.. And then i'd help you port-forward just in case..

As far as the 'mis-behaving' is concerned.. That is what software updates are for.. Just get Peer Guardian 2 and you'd be fine..

Ps: Scroll down for Visuals

x|D