SIP in nat configuration problem
We have a fortinet firewall: FortiGate 311B Firmware Version v5.2.3,build670 (GA) [Update] We are working in NAT configuration Poort 1 is used for management. Poort 2 is uplink to outside world The other ports are aggregated in one pipe with each of them having there own small subnet. third digit representing the port number. Registration is not ok, due to NAT problem I attached 195.207.5.83 : public ip on the internet side. 10.40.5.135 : local ip assigned to ALU equipment Fortinet firewall should do the NAT to translate the IP. Attached trace is taken on the ALU equipment, public ip should not be seen in SIP reply messages sent to ALU equipment. See packet 4 in register_nok_fortinet_problem.pcap In packet 4 the ip in the contact header from the public side should be replaced by isam IP again. Now it is : sip.Contact == "<sip:01150900027@195.207.5.83:50177>;expires=120" It should be replaced by : sip.Contact == "<sip:01150900027@10.40.5.135:50177>;expires=120" SIP session Helper is disabled.
It seems the private IP is not translated anymore into the public ip. On the internet side we can see 10.40.5.135. I expect the public internet ip 195.207.5.83 would always be used at internet side.
Are we missing somehow a parameter in the configuration or is this still some firmware problem?