I have an asterisk server and multiple phones behind a NAT router. The asterisk uses SIP accounts on a SIP service provider to make calls (blueface.ie). I have a static IP address and so I have set up the Blueface accounts to forward traffic to to my Asterisk server using DDI over a single trunk account that is registered in sip.conf.
When the asterisk server starts up it sends the REGISTER command to Blueface for the SIP trunk. The incoming calls then work for 45 seconds and then stop working. 53 seconds later (98 seconds after the previous REGISTER command), asterisk re-registers and the cycle is repeated. For the calls that fail during that 53 seconds there is no traffic received by the Asterisk server from Blueface when an inbound call is attempted.
I’ve checked my router and there is no time-outs set to 45 seconds. Also, I have 4 SIP phones that connect directly to blueface behind the same NAT that don’t have the same problems.
Any help would be appreciated.