Enabling Remote NAT Traversal
Applies to version: v2.7.
To enable Remote NAT Traversal:
1- Select NAP from the navigation panel
2- Select a SIP NAP from the Network Access Point List
- Click Edit
3- In the section Network Address Translation:
- Choose the proper Remote Method.
- Click Save
Here's more useful regarding the 3 Remote NAT Traversal Methods:
No NAT
When the local endpoint is NOT behind a NAT. This means, your local endpoint has a Public IP address. Public means the IP address is globally routable on the Internet. If you're not sure, you can refer to http://en.wikipedia.org/wiki/Private_network.
Force Passive Mode
The TMG will NOT send any RTP packet and wait for the first RTP packet. The remote endpoint will send the first RTP packet. It will ignore the IP address/port sent in the SDP (in the SIP '200 OK' message)and use the IP address/port from where it received the RTP packet.
Note: If the remote endpoint is also set as passive, this method will not work, since both side will wait for the first incoming RTP packet.
Parse Direction Attribute
TMG will look in the SDP to find an attribute direction:active. If it find this attribute, TMG will act exactly as the “Force Passive Mode” method. In fact, this a dynamic way to enable the “Force Passive Mode”.