In this article, we will show you how to disable SIP ALG on FortiGate. On devices running FortiOs, you will need to disable this in multiple places as shown below.
1. Open the Fortigate CLI from the dashboard
2. Enter the following commands in FortiGate’s CLIconfig system settings
set sip-helper disable
set sip-nat-trace disable
reboot the device
3. Reopen CLI and enter the following commands (do not enter the text after //)config system session-helper
show //you need to find the entry for SIP, usually 12, but can vary
delete 12 //or the number that you identified from the previous command
4. Disable RTP processing as follows:config voip profile
set rtp disable
There might be other settings that you need to configure depending on the FortiOS version that you are using. If you continue encountering issues related to SIP ALG, please contact Fortinet Support.