To Disable ALG

Step #1 – Removing the session helper.

A. Run the following commands:

config system session-helper
  show

Amongst the displayed setting will be one similar to the following example:

    edit 13
        set name sip
        set protocol 17
        set port 5060
 
B.  in this example the next commands would be:

delete 13
end

Step #2 - change the default –voip –alg-mode.

Run the following commands:

config system settings
set default-voip-alg-mode kernel-helper based
end

Step #3 – Either reboot or clear sessions to make sure changes take effect