SIP (Session Initiation Protocol) is a key protocol used to establish and manage VoIP calls, supporting features like device registration, call presence, and audio session management. Essentially, it’s the backbone that powers VoIP communication.

ALG (Application Layer Gateway), as it relates to SIP, is a function found on many routers and firewalls. Its role is to modify SIP traffic by rewriting destination information to assist in specific network configurations.

Why Should SIP ALG Be Disabled?

While SIP ALG may sound beneficial, in practice, it often causes more problems than it solves. By altering SIP traffic, SIP ALG can redirect it to non-existent addresses, leading to common issues such as:

• Dropped calls
• Inability to receive incoming calls
• Phone registration issues
• Phones continue to ring after being answered

Because SIP ALG interferes with the normal flow of VoIP traffic, disabling it is usually recommended to prevent these connectivity problems.

How to Disable SIP ALG

Most modern routers and firewalls allow SIP ALG to be toggled on or off. 

Contact Your IT Professional
If you're working with an IT team, ask them to disable SIP ALG on your network devices. If you handle your office network, search for instructions specific to your router model by combining the router name and “disable SIP ALG” in your search query.

Contact our Technical Support Team 
Our support team can help you find the right instructions for disabling SIP ALG on your network equipment. Once it’s disabled, we can verify the change and monitor your network for any further issues.