SPA504G no incoming calls

[Mates3000]

I have an issue with a Cisco SPA504g handsets connected to an Elastix server.

I have the same issues at two different locations. One location the service phone connects to an SF100D-16P and a Billion 7800NXL. The other location is connected to a Netgear CG3000v2 with nothing else in between.

The elastix server is hosted in a data centre.

This issue is as follows:

• Phones are connected and can make and receive calls
• The internet connection drops offline and then reconnects.
• The modem remains switched on all the time.
• The phone and the Elastix server both act as if they are still connection.
• When I make an outgoing call it still connects.
• Incoming calls will not register on the phone after the loss and recovery of the connection.
• If i restart the handset it recovers and can receive incoming calls or if i restart the phone system the handset can receive calls.

I have tried:

• opening up ports 5000 - 6000 and 10000 - 20000
• I have updated the firmware on the phones to the latest firmware.
• Adjusting some of the SIP Timer settings in the handset.
• Had a cisco online support person log into the phone and check out the settings.

I have been at this problem all day without success. 

[Dan Lukes]

Your description is somewhat unclear to me.

The internet connection drops offline and then reconnects

What you mean saying "internet connection" ? The Ethernet link ? IP address has been lost ? Packets are lost in transmit ? And the "internet connection" has been lost between whom and whom ?

Incoming calls will not register on the phone

SPA504G register itself to Elastix PBX. Elastix doesn't REGISTER to SPA504G. So I'm not sure what you mean saying "call from Elastix to SPA504G is not registered" at the packet level.

[Mates3000]

Ok issue resolved. 

Keep NAT Alive setting switched on the SPA504G from no to Yes.

Works perfectly and recovers from a lost connection everytime.

The connection loss is when the DSL connection drops sync and then recovers.

[Dan Lukes]

Oh, you didn't mentioned there's NAT between phone and Elastix ...

Glad to hear you solved the issue.