Scope:The following article will show you how to disable the SIP ALG setting on a Fortigate Firewall.Requirements:CLI access to the Fortigate FirewallDisabling SIP ALGOpen the CLI interface for your Fortigate FirewallBefore making any changes be sure to backup your configurationIn the CLI enter the following commandsUse the following commands for a device on FortiOS starting at 6.2.2config system settingsset sip-expectation disableset sip-nat-trace disableset default-voip-alg-mode kernel-helper-basedendFor devices below FortiOS version 6.2.2 use the following commandsconfig system settingsset sip-helper disableset sip-nat-trace disableset default-voip-alg-mode kernel-helper-basedendIf you encounter and error while entering set default-voip-alg-mode kernel-helper-based go ahead and ignore itThe rest of the configuration will be the same for all FortiOS versionsRun the following commandsconfig system session-helpershow Here you will want to find the entry for SIP, this is typically 13 but it may differ depending on software version and modeldelete 13endEnter the following commands in the CLI to disable RTP processingconfig voip profileedit defaultconfig sipset rtp disable**some models also require**set status disableendendOnce done reboot the device, Fortigate firewall to activate the session helper changesLastly, reboot all SIP Devices/Phones