Speech path issues on SIP Trunks

If users are experiencing speech path issues on SIP trunks, please check the following:

SIP Settings

  1. Navigate to SIP Settings page, verify the parameters under NAT settings.
  2. Ensure External IP is configured with the correct external IP address.
  3. Check that Local Networks is properly configured.

TIP: You can click on Auto Configure to let the system detect and automatically populate the values for External IP and Local Networks.

Port Forwarding

Typically, the UCx server is deployed behind a router that implements NAT/PAT between the UCx server and the Internet. In order for the UCx system to properly establish voice path for SIP trunks calls in all possible scenarios, it is necessary to enable port forwarding of RTP ports to the UCx server.  This is done on the router. The RTP port range (by default 10000 to 13999) must be forwarded to the IP address of your UCx Server (by default 

Rule Name Port Number/Port Range Port Type
RTP (media) 10000 - 13999 UDP


If there is a firewall implemented on the network, ports 10000-13999 need to be opened.


If SIP ALG exists on any router or firewall in the network, make sure they are all disabled. See Unexpected call failures and registration problems for details.

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