SPA112 Reboots on Answering Call

[RBShaw]

I am connected to a hosted VOIP service with an SPA112. Most times, incoming and outgoing calls work fine. Occasionally, perhaps one time in ten, the phone rings then when the call is picked up the SPA reboots. I always wait for the caller ID before answereing, so the phone has rung two or three times. I suspected the hardware, so I replaced the SPA, but the second unit has the same problem.

Product Name: SPA112
Software Version: 1.4.1(SR5) Hardware Version: 1.1.0

[Dan Lukes]

I assume it chokes on something in SIP packet sent by upstream proxy.

Turn on and capture debug messages, capture SIP packets between device and proxy and we can try to identify the issue cause then.

[RBShaw]

I suspect that the problem is related to my router firewall. The day after I posted the original message, the SPA stopped registering and rebooting it did not help. Since it was during the work day, I could not reset the router, so I moved the SPA to another router that has NAT but no firewall. The SPA registered and has been working fine for 18 hours or so. I will have to give it some more time to see if the reboot problem comes back.

My main router is running PFsense and is configured with NAT, no incoming port forwarding, and no special firewall rules for SIP. The SPA has the NAT Mapping Enable and NAT Keep Alive Enable set to Yes, so it should be okay working with NAT. Any ideas on how the firewall might be causing the problem?

[RBShaw]

With the SPA on the router with no firewall, the SPA rebooted three times in a row when the incoming call was from a FAX machine. Unfortunately there is no Syslog server on that LAN so I don't have the log. Since it now seems to not be the firewall, as long as it will register, the next thing to try is to go back to the main LAN that has the Syslog server and try to capture a log.

[Dan Lukes]

You need no syslog server. Just capture syslog packets on the wire by a packet catcher. Content of them is human readable.

[RBShaw]

To be sure it was not a problem that only affected secure calls, I turned off secure calls and TLS, and am now running straight UDP. The attached log captured the call that crashed the phone.

[Dan Lukes]

Well, the log doesn't help to identify the cause and you didn't catched SIP packets, so we know no content of them.

With the SPA on the router with no firewall, the SPA rebooted three times in a row when the incoming call was from a FAX machine.

So there's no issue for plain voice incoming call ? Then the issue must be related to T.38 codec renegotiation. Reconfigure T.38 parameters or disable T.38 at all.

See also: SPA ATA: Fax--T.38 Basic Configuration