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VoIP Compatibility with Arris/Motorola DG860A: Disabling SIP ALG

The Arris/Motorola DG860A is a popular modem-router unit known for its robust performance in internet connectivity. However, when it comes to VoIP (Voice over Internet Protocol) services, users might face certain challenges. A primary source of these challenges is often the SIP ALG (Session Initiation Protocol Application Layer Gateway) feature. This article aims to provide insight into the VoIP compatibility issues with the DG860A and a guide on how to disable SIP ALG to potentially resolve these problems.

VoIP Compatibility Issues with the DG860A

Understanding VoIP and the DG860A

VoIP technology allows voice communication over the internet.
The DG860A, designed to handle high-speed internet, may have firmware or network configurations that are not fully optimized for VoIP.

SIP ALG and Its Impact on VoIP

SIP ALG is integrated into many routers, including the DG860A, to assist VoIP traffic in navigating through the network.
Ironically, SIP ALG can interfere with VoIP call signaling, leading to issues like call dropping, one-way audio, and registration failures.

Disabling SIP ALG on the Arris/Motorola DG860A

To enhance VoIP compatibility, disabling SIP ALG is often recommended. Here are the steps to do so:

Step 1: Accessing the Router's Interface

Connect to Your Network: Use a computer or device connected to your DG860A network.
Enter the Router IP: Open a web browser and type in the default IP address for the DG860A, often
Log In: Enter your admin username and password to access the router settings.

Step 2: Navigating to SIP ALG Settings

Find the Advanced Settings: Once logged in, navigate to the 'Advanced' tab or section in the router's web interface.
Locate the NAT or Firewall Settings: SIP ALG settings are typically found under these categories.

Step 3: Disabling SIP ALG

Identify the SIP ALG Option: Look for a checkbox or toggle labeled as ‘SIP ALG’.
Disable SIP ALG: Uncheck the box or set the toggle to ‘Off’.
Apply Changes: Save your settings to ensure the changes are implemented.
Restart the Router: Reboot your DG860A to ensure the new configuration takes effect.


Understanding the role of SIP ALG in VoIP issues and how to disable it on your Arris/Motorola DG860A can significantly improve your VoIP experience. While SIP ALG is meant to facilitate VoIP traffic, it often does the opposite, leading to various call quality and connectivity issues. By following the steps above, you can optimize your router for better VoIP performance.

Updated on: 01/22/2024