Sip Trunk Registration Not Automatically Refreshing

[Tyler Phelps]

Has anyone run into the issue where the SIP Trunk registration is automatically showing an update registration? Our Trunk provider is Sip.US. In the options tab I have set the registration timeout to 1 minute. The trunk provider is seeing a 200 ok message come from us every 60 seconds or so and in their world they are saying that the registration is good. On our side the only time that the registration time or date refreshes is when I manually push refresh registration. I am seeing on the SIP.US call log that calls are being attempted but they are never hitting our PBX and they claim it is due to UDP timeout on our firewall. Our UDP timeout is set to 7 days now temporarily until I can get this issue rectified. It seems after I manually refresh the registration from inside of 3CX all is well in the world of phones again.

 

[cobaltit]

Step one, configured your firewall properly. Static Port forwarding eliminates the UDP timeout bit which is why it's why 3CX recommends you set it up that way. And 3CX is reporting the information correctly. You only register once and then you are refreshing the registration. This is a firewall problem and not a 3CX or SIP trunk problem.

 

[Tyler Phelps]

@cobaltit I do have that setup. What I didnt do is set it to any external. I set it to static IP addresses of the SIP trunk provider, and our remote sites that use SBC. Do you still think that is the problem?

 

[YiannisH_3CX]

Hello @Tyler Phelps

The re-registration timeout between the PBX and the trunk is decided and set by the provider. When sending a registration request to the provider the value in the trunk settings is suggested to the provider. The real timeout will be set in the Providers 200 OK message and the PBX will follow that value as the set re-registration value. The PBX will then try to re-register in the 90% of the agreed value.
SIP.US i believe is one of the rare cases where the provider agrees to the suggested value from the PBX so the set value should be 60 seconds.
So if you run a capture on the PBX you should see the PBX trying to re-register every 54 seconds. If the registration is OK then try to make a call and see if it is hitting the PBX. If not then you probably have a firewall issue.

 

[cobaltit]

@Tyler Phelps I'd try setting your UDP timeout back to normal and relaxing the firewall. It's possible that SIP.US uses a range and your forwarding is blocking traffic. If that doesn't resolve it then confirm the behavior. Typically when it's a UDP timeout issue what will happen is you can always make outbound calls but you can only receive calls with-in the timeout period between the refresh and the timeout. So if your refresh is every 60 seconds and your UDP timeout is 30 seconds then you effectively have about 30 seconds where you won't be able to receive calls. In those cases you can either set your firewall UDP timeout to something the same or longer than the SIP registration interval (60 seconds in this case) or you can try the keep-alive function under Network Settings in 3CX.