SIP Configuration for Remote Symmetric NAT Traversal

Applies to version(s): v3.0

We assume at this point that a SIP NAP or a SIP Open NAP has already been created and allocated.

To configure a Remote Symmetric NAT Traversal

1. Select NAPs in the Navigation Panel:

2. Select an existing SIP NAP in the list:

3. Click on Network Address Translation (NAT):

4. SBC/Tmedia can be configured for RTP messages traversing a remote NAT as follows:

• None: Remote device is not behind a NAT or remote NAT device is SIP/RTP aware.
• Force Passive Mode: Uses IP address and port from first received RTP packet to start sending RTP packets.
• Parse Direction Attribute: Uses "Passive Mode" only when "a=direction:active" is received in the SDP.
  

Select the appropriate method for RTP NAT Traversal.

5. SBC/Tmedia can be configured for SIP messages traversing a remote NAT as follows:

• None: Remote device is not behind a NAT, or reports SIP headers (contact, via) that are directly reachable.
• Automatic NAT Traversal: Automatically detects if the device is behind a NAT. This method parses the Contact IP address of the packet and check if it corresponds to a private/reserved IP range. In that case, SIP messages will be sent to the IP/Port seen in the IP header rather than the SIP headers.
• Force Use of Public IP and Port: Uses the IP and port from the IP header of the last received SIP packet.
  

Select the appropriate method for SIP NAT traversal.

6. Click on the button Save.