I have a Linksys PAP2 behind a D-Link DSL-2540b Modem/Router. The modem and ATA are both new and whenever AT&T changes the WAN IP, the ATA stops registering with my asterisk server. The asterisk server has a static IP and isn’t behind any NAT; so that’s not an issue on that end. If I change the port on the ATA or reboot the modem, suddenly the ATA registers fine and everything works again until the IP changes.
Here’s what I’ve tried so far:
I’ve tried a STUN server,
changing the registration time from 3600 to 600,
numerous settings in the modem/router (dmz the ATA, forwarding ports, differentiated services/QoS, etc.)
I also just changed the SIP T1 to 1 and the Reg Retry Long Intvl to 120 instead of 1200; but I don’t have much hope for these fixes. I’ve searched for people having similar problems and it seems like everyone fixes the problem by buying different devices. Though it’s not always a 2540b and a PAP2 causing the issue. I’m willing to buy a new modem or swap out the ATA if necessary; but I’m hoping someone can tell me what I’m missing to fix this issue. Any advice/help is greatly appreciated and let me know what additional info you need to help diagnose the problem.