Note that, as this process may temporarily interrupt your internet connection and phone service, we recommend doing this in an off-peak period or outside of business hours.
Learn more about SIP ALG in our knowledge base article here: SIP ALG
Disabling SIP ALG
Login to the Sophos CLI using Telnet or SSH. You can also access the CLI from admin > Console in the upper right corner of the Admin Console screen.
Enter option 4 to connect to the Device Console
Execute the following command:
console> system system_modules sip unload