Chapter 22 VoIP Solutions: SIP : FortiGate VoIP solutions: SIP : How the SIP ALG performs NAT : Translating SIP session destination ports : Translating SIP sessions to a different destination port
  
Translating SIP sessions to a different destination port
To configure translating SIP sessions to a different destination port you must add a static NAT virtual IP that translates tie SIP destination port to another port destination. In the example the destination port is translated from 5060 to 50601. This configuration can be used if SIP sessions uses different destination ports on different networks.
Figure 302: Example translating SIP sessions to a different destination port
To translate SIP sessions to a different destination port
1. Add the static NAT virtual IP.
This virtual IP forwards traffic received at the port1 interface for IP address 172.20.120.20 and destination port 5060 to the SIP server at IP address 192.168.10.20 with destination port 5061.
config firewall vip
edit "sip_port_trans_vip"
set type static-nat
set portforward enable
set protocol tcp
set extip 172.20.120.20
set extport 5060
set extintf "port1"
set mappedip 192.168.10.20
set mappedport 50601
set comment "Translate SIP destination port"
end
2 Add a security policy that includes the virtual IP and the default VoIP profile.
config firewall policy
edit 1
set srcintf "port1"
set dstintf "port2"
set srcaddr "all"
set dstaddr "sip_port_trans_vip"
set action accept
set schedule "always"
set service "ANY"
set utm-status enable
set profile-protocol-options default
set comments "Translate SIP destination port"
end