GXP-1628 won't register

[nickb]

I’m running FreePBX 12.7.6-1904-1.sng7 using the commercial EPM, on a system with 73 extensions. Most of these (about 65) are managed by the EPM; a few unsupported devices are manually configured. The system is fully updated in Yum and Module Admin.

Nearly all devices are Cisco SPA500 series. Recently we added six Grandstream GXP-1628 devices, configured via commercial EPM.

These devices successfully provision (verified in apache log) and have the correct information in the provisioning files for SIP server and ports. I am using PJSIP.

All six devices will only show “Unavailable” in SIP Peers. Attempting to dial one of these extensions from another results in the call going directly to voicemail. They can, however, dial voicemail, receive a password prompt from the server, subsequently interacting with the voicemail subsystem.

Suspecting a NAT issue in the router at the client site, we verified SIP ALG was disabled, and changed NAT settings to the recommended values for a SonicWall per the documentation that the site network admin referenced (I do not have that documentation). The UDP NAT timeout is 30 seconds in the router, so I changed Register Expiration to 1 minute, and ReRegister Before Expiration to 40 seconds in the Basefile Editor for the Grandstream template, this should result in re-registration before the 30 second UDP NAT timeout happens.

However, not even the initial registration is received when the phones are booted. I did reboot the FreePBX server as well, but no change in behavior occured after rebooting.

I’ve also verified that the site IP address is in the “Local” networks group in the Firewall, and is whitelisted in Intrusion Detection.

Any suggestions as to why the phones may not be registering at all?

[arielgrin]

Are the phones on the same local network as FreePBX?

[cynjut (Dave Burgess)]

@nickb

All six devices will only show “Unavailable” in SIP Peers.

Look through the /var/log/asterisk/full file and search for the extension number. That will give you the sequence of processing that is succeeding, then failing.

To be honest, this doesn’t really sound like a traditional RTP error. I suspect more of a routing issue, although depending on the router configs and where the phones are relative to your network equipment, it could be a problem with NAT not allowing the phone to stay registered.

Logs are going to tell the story.

[nickb]

No, the phones are at a remote location behind a SonicWall router.

[nickb]

Other than failed calls to the extension, this is all I see in the logs (actual public IP address replaced with 1.2.3.4 for privacy):

[2019-09-10 13:46:36] VERBOSE[11184] res_pjsip/pjsip_configuration.c: Endpoint 600 is now Reachable
[2019-09-10 13:46:36] VERBOSE[11184] res_pjsip/pjsip_options.c: Contact 600/sip:[email protected]:60274 is now Reachable.  RTT: 63.050 msec
[2019-09-10 13:47:39] VERBOSE[31398] res_pjsip/pjsip_configuration.c: Endpoint 600 is now Unreachable
[2019-09-10 13:47:39] VERBOSE[31398] res_pjsip/pjsip_options.c: Contact 600/sip:[email protected]:60274 is now Unreachable.  RTT: 0.000 msec
[2019-09-10 13:50:23] VERBOSE[12176] res_pjsip/pjsip_options.c: Contact 600/sip:[email protected]:60274 is now Unreachable.  RTT: 0.000 msec
[2019-09-10 13:52:53] VERBOSE[12176] res_pjsip_registrar.c: Removed contact 'sip:[email protected]:60274' from AOR '600' due to request
[2019-09-10 13:52:53] VERBOSE[12178] res_pjsip/pjsip_options.c: Contact 600/sip:[email protected]:60274 has been deleted
[2019-09-10 13:52:53] VERBOSE[12176] res_pjsip_registrar.c: Added contact 'sip:[email protected]:39062' to AOR '600' with expiration of 3600 seconds
[2019-09-10 13:52:54] VERBOSE[12176] res_pjsip/pjsip_configuration.c: Endpoint 600 is now Reachable
[2019-09-10 13:52:54] VERBOSE[12176] res_pjsip/pjsip_options.c: Contact 600/sip:[email protected]:39062 is now Reachable.  RTT: 95.631 msec
[2019-09-10 13:52:55] VERBOSE[12176] res_pjsip_registrar.c: Removed contact 'sip:[email protected]:39062' from AOR '600' due to request
[2019-09-10 13:52:55] VERBOSE[12178] res_pjsip/pjsip_options.c: Contact 600/sip:[email protected]:39062 has been deleted
[2019-09-10 13:52:55] VERBOSE[12178] res_pjsip/pjsip_configuration.c: Endpoint 600 is now Unreachable
[2019-09-10 13:52:55] VERBOSE[12176] res_pjsip_registrar.c: Added contact 'sip:[email protected]:39062' to AOR '600' with expiration of 3600 seconds
[2019-09-10 13:52:55] VERBOSE[12176] res_pjsip/pjsip_configuration.c: Endpoint 600 is now Reachable
[2019-09-10 13:52:55] VERBOSE[12176] res_pjsip/pjsip_options.c: Contact 600/sip:[email protected]:39062 is now Reachable.  RTT: 112.011 msec
[2019-09-10 13:53:58] VERBOSE[12176] res_pjsip/pjsip_configuration.c: Endpoint 600 is now Unreachable
[2019-09-10 13:53:58] VERBOSE[12176] res_pjsip/pjsip_options.c: Contact 600/sip:[email protected]:39062 is now Unreachable.  RTT: 0.000 msec

[arielgrin]

It seems as if the router is closing the session. Make sure that your router is not closing the session before the phone re-registers.
Check the SIP ALG on router.

[nickb]

SIP ALG is disabled (which is nearly universally recommended to be disabled, from what I’ve found).

I also suspected the router of closing the session, but the re-reg timeouts should be shorter than the NAT timeouts, which should keep the session open.