FortiGate

For FortiGate with FortiOS >= 5.2.

• Log in to your FortiGate as administrator
• Connect to the CLI Console and enter the following commands

Remove the SIP Session Helper

show system session-helper

Search for the rule with port 5060 (normally it is the rule number 13) and remove it with the following commands.

config system session-helper
    delete 13
    end

Set the SIP ALG mode

Has to be done for each VDOM.

config system settings
    set sip-tcp-port 9999
    set sip-udp-port 9999
    set default-voip-alg-mode kernel-helper-based
    end

Deactivate the SIP ALG

Has to be done for each VDOM.

config voip profile
    edit default
        config sip
            set status disable
            set rtp disable
            set strict-register disable
        end
     end

Don’t forget to reboot your firewall or to clear the sessions!