Switchvox - How can I solve the Digium phone incompatibility with ASUS RT-AC66U?

 There is a known incompatibility between the  ASUS RT-AC66U devices and the Digium Phones. The problem is that phones enter in a rapid loop of contacting the server and fetching configuration.

Solution:

In order to work around this issue, it is necessary to disable SIP ALG and and SIP pass-trough.

1. Enable telnet to the device via the web GUI.

2. Log into the device using telnet with the appropriate IP address.

telnet xxx.xxx.xxx.xxx

3. Issue the following command.

   1. nvram get nf_sip  (the output should be a '1')

   2. nvram set nf_sip=0 nvram commit

4. Now you should reboot.

5. From the web GUI of the router.

   1. Go to Advanced Settings / WAN on left side.

   2. From the tabs across the top, choose NAT pass through

   3. Choose SIP pass through to disable

   4. Press 'Apply'

6. Wait for the phones to pick up the new NAT table during their the next registration or reboot each phone to pick up the change immediately.