Outbound call failures "required: unsupported:sdp-anat"

I’ve been using FreePBX now with no real issues for >1 year with a Cisco 9971. The only changes have been updates to keeping the system patched. Yesterday I had to reboot the system for the first time in months and while incoming calls still work, outgoing now fails with the following error:

[2017-07-16 08:26:49] WARNING[859][C-0000000a]: chan_sip.c:25808 handle_request_invite: Received SIP INVITE with unsupported required extension: required: unsupported:sdp-anat

I did find this topic INVITE with unsupported required extension however I don’t see any Allow fields in the extension (at least in the web UI) to modify. I’m hoping I am missing something obvious but I figured it would be good to make a post as others are much better than I am at this and may be able to direct me faster.

At the moment the server is fully up to date and indicating it is FreePBX


Anyone have any ideas?

https://community.asterisk.org/t/asterisk-cisco-cp-9971-sdp-anat/67869 is a start. Granted, not a good one, but a start.

https://supportforums.cisco.com/discussion/13078491/sdp-anat-cme-9971-sip is a little better.

Yea I had reviewed those but didn’t find any successful options. The odd thing is that this phone had been fully working for over a year with no issues. I haven’t changed the config file or firmwares on it. The only thing that has changed is FreePBX updates which leads me to believe that there was something changed in Asterisk or FreePBX that used to allow it to work but doesn’t anymore.

  • Update: may not be Asterisk/FreePBX. I recently changed DHCP servers and it seems I no longer have Option 150 in there for this reservation. I’m addressing that now and will retest once I get that added.

Looks like that was it! For those that run into this issue in the future - make sure your TFTP server is defined correctly. Turns out my phone was no longer getting Option 150 so it didn’t get its updated configuration (the phone was functional using a previous config file it had saved it seems). Once I added Option 150 back in and defined the TFTP server, rebooted the phone and all is well!