Problem protocol sip with Fortigates Fixed

Here entry 13 is the one which points to SIP traffic which uses UDP port 5060 for signaling.

In this example, the next commands to remove the corresponding entry would be:

# config system session-helper
    delete 13

end

Change the default–voip–alg-mode.

# config system settings

    set default-voip-alg-mode kernel-helper-based

    set sip-helper disable

    set sip-nat-trace disable

end

Note that since version 6.2.2 the CLI command is different:

# config system settings

    set default-voip-alg-mode kernel-helper-based

    set sip-expectation disable

    set sip-nat-trace disable

end

Clear Sessions.

# diagnose system session filter

or reboot device.

# execute reboot

Source: https://kb.fortinet.com/kb/documentLink.do?externalID=FD36405