Chapter 22 VoIP Solutions: SIP : FortiGate VoIP solutions: SIP : How the SIP ALG performs NAT : SIP NAT configuration example: destination address translation (destination NAT) : General configuration steps
  
General configuration steps
The following general configuration steps are required for this destination NAT SIP configuration. This example uses the default VoIP profile.
1 Add the SIP proxy server firewall virtual IP.
2 Add a firewall address for the SIP proxy server on the private network.
3 Add a destination NAT security policy that accepts SIP sessions from the Internet destined for the SIP proxy server virtual IP and translates the destination address to the IP address of the SIP proxy server on the private network.
4 Add a security policy that accepts SIP sessions initiated by the SIP proxy server and destined for the Internet.