Cisco SPA525-G2 Inbound Calls Failing After an Interval

[Rick Thomas]

We have some Cisco SPA525-G2 phones deployed with a client who is using a cloud based SIP PBX.  The phones register fine, and outbound calls work fine.  Inbound calls work fine for about 2-3 minutes, but after that interval time period passes, the phones become unreachable and we get a message from the PBX stating that the extension is currently unavailable.

I poked around at the NAT settings on the phone, and don't see anything too useful there.  The NAT keepalive interval for the phones is set to 15 seconds.  I believe the client has a Cisco or Sonicwall firewall out in front of the phones.

Any tips or pointers are much appreciated!

Cory

[rowseyba1]

Cory,

If it's a Sonicwall firewall, check the firewall logs and see if it is dropping the calls.  I've seen the Sonicwall do this periodically.  Also, as a test, take one of the phones out from behind the firewall and see if the calls still drop.  Ditto if it's a Cisco firewall.  Check the logs and see if it's blackholing it for some reason.