Phone won't connect to PBX server "no service" message, nothing in asterisk log

I’m getting a “no service” message on the phone, and there is nothing in /var/log/asterisk/full (no failure, or registered/unregistered message).

According to netcat I can reach port 5060:
$ nc -vnzu 12.154.x.x 5060
Connection to 12.154.x.x 5060 port [udp/*] succeeded!

Any ideas why the phone can’t connect, and asterisk doesn’t even see it as trying to connect?


Is the phone on the same LAN as the PBX? If not, please describe network (NATs, firewalls, etc.) If the phone is behind a NAT and not doing its own mapping, check that you have the extension set up for NAT.

Can a softphone on the same LAN as the IP phone register to your PBX? If not, and the softphone doesn’t say what’s wrong, run Wireshark on the softphone PC to see what responses, if any, are being received for the REGISTER requests.

If there are no responses at the softphone, run tcpdump on the PBX to see whether any requests are coming in and whether any responses are being sent.

If the softphone works ok, use the IP phone’s debug facilities to check its requests and responses, or rig a way (managed switch, dumb hub or PC with two NICs) to capture the phone’s traffic.

If you still have trouble, post phone make/model, whether this once worked (if so, what’s changed), whether other phones or devices register ok to the PBX, whether the phone can register to other servers, etc.