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VoIP Compatibility with Verizon FiOS G1100 Modem: Disabling SIP ALG

The Verizon FiOS G1100 is a modem-router combo often used in home and small business environments, notable for its compatibility with high-speed internet. When it comes to VoIP (Voice over Internet Protocol) services, however, users may encounter specific challenges. A significant factor contributing to these challenges is the SIP ALG (Session Initiation Protocol Application Layer Gateway) feature. This article examines VoIP compatibility issues with the Verizon FiOS G1100 and provides a guide on how to disable SIP ALG, which may improve VoIP performance.

VoIP Compatibility Issues with the Verizon FiOS G1100

Overview of VoIP and the G1100

VoIP technology enables voice communication over internet protocols.
The G1100, designed primarily for internet services, might have configurations or firmware that are not fully optimized for VoIP.

The Role of SIP ALG in VoIP Issues

SIP ALG is included in many routers, including the G1100, to facilitate the passage of VoIP traffic.
In many cases, SIP ALG can disrupt VoIP functionality, leading to issues like impaired call quality, connection difficulties, and dropped calls.

Disabling SIP ALG on the Verizon FiOS G1100

Disabling SIP ALG is often a recommended step to mitigate VoIP-related issues. Follow these steps to disable SIP ALG on the G1100:

Step 1: Accessing the Router Interface

Connect to Your Network: Ensure your device is connected to the G1100 network.
Open the Router IP: Launch a web browser and enter the G1100's default IP address, usually
Log In: Use your administrator credentials to access the router settings.

Step 2: Locating SIP ALG Settings

Navigate to Advanced Settings: Look for an 'Advanced' section or tab in the router's interface.
Find Firewall or Security Settings: SIP ALG settings are commonly located in these sections.

Step 3: Turning Off SIP ALG

Identify the SIP ALG Setting: Search for an option labeled ‘SIP ALG’ or similar.
Disable SIP ALG: Disable the feature by unchecking its box or toggling it off.
Save Your Settings: Ensure that changes are applied by saving the configuration.
Restart Your Router: Reboot the G1100 to activate the new settings.


VoIP compatibility issues with the Verizon FiOS G1100 modem can often be addressed by disabling the SIP ALG feature. While intended to aid VoIP traffic, SIP ALG frequently causes more problems than it solves. By following the outlined steps, users can enhance their VoIP service quality, leading to clearer and more reliable voice

Updated on: 01/22/2024