WSL2 Loses Communication with Windows Firewall on Windows 11

Introduction

Windows Subsystem for Linux version 2 (WSL2) is a significant improvement over its predecessor, WSL, providing better performance and full system call compatibility. However, some users have reported issues with WSL2 losing communication with the Windows firewall in Windows 11. This article will discuss the possible causes and solutions for this problem.

Understanding WSL2 and Windows Firewall

WSL2 is a compatibility layer for running Linux binary executables natively on Windows 10 and Windows 11. It utilizes a lightweight virtual machine to provide an isolated Linux environment that can coexist with Windows applications. The Windows firewall is a security feature that controls incoming and outgoing network traffic based on a set of rules and policies.

WSL2 Network Configuration

WSL2 uses a virtual Ethernet adapter to connect to the host Windows system. By default, WSL2 uses the 172.22.32.1 IP address as its DNS server and gateway address. This configuration allows WSL2 to communicate with the Windows host and the internet.

Windows Firewall Configuration

The Windows firewall has default rules that allow outgoing traffic and block incoming traffic. However, you can create custom rules to allow or block specific traffic based on the application, port, or protocol. When WSL2 loses communication with the Windows firewall, it is likely due to a misconfiguration or a conflict between WSL2 and the firewall rules.

Possible Causes and Solutions

The following are some possible causes and solutions for WSL2 losing communication with the Windows firewall in Windows 11.

Firewall Rules

One possible cause is that the firewall rules are blocking WSL2 traffic. To resolve this issue, you can create a new inbound rule that allows traffic to and from the WSL2 virtual Ethernet adapter. Here are the steps to create the rule:

1. Open the Windows Defender Firewall with Advanced Security console.
2. Click on Inbound Rules and then New Rule.
3. Select the Custom option and click Next.
4. Select the All programs option and click Next.
5. Select the Protocol type and specify the ports if necessary.
6. Select the Allow the connection option and click Next.
7. Select the network locations and click Next.
8. Specify a name and description for the rule and click Finish.

Virtual Machine Platform Service

Another possible cause is that the Virtual Machine Platform service is not running. This service is responsible for managing the WSL2 virtual machines and their network configuration. To check if the service is running, follow these steps:

1. Press the Windows key + R to open the Run dialog box.
2. Type services.msc and press Enter.
3. Scroll down to the Virtual Machine Platform service.
4. Check if the service is running and its startup type is Automatic.
5. If the service is not running, right-click on it and select Start.

Windows Updates

A third possible cause is that there are pending Windows updates that need to be installed. Windows updates can include security patches and bug fixes that can resolve compatibility issues between WSL2 and the Windows firewall. To check for updates, follow these steps:

1. Click on the Start button and select Settings.
2. Click on Windows Update and then Check for updates.
3. Install any available updates and restart the system if necessary.

WSL2 losing communication with the Windows firewall in Windows 11 can be caused by misconfigured firewall rules, a non-running Virtual Machine Platform service, or pending Windows updates. By following the steps outlined in this article, you can troubleshoot and resolve the issue, ensuring that WSL2 can communicate with the Windows firewall and the internet.

References

• Microsoft. (2021). Troubleshoot issues with the Windows Subsystem for Linux (WSL) on Windows 10. https://docs.microsoft.com/en-us/troubleshoot/windows-client/shell-experience/troubleshoot-wsl

• Microsoft. (2021). Create a custom Windows Defender Firewall rule. https://docs.microsoft.com/en-us/windows/security/threat-protection/windows-firewall/create-a-custom-rule-for-windows-defender-firewall

• Microsoft. (2021). Enable or disable the Windows Subsystem for Linux (WSL) service. https://docs.microsoft.com/en-us/windows/wsl/troubleshooting#enable-or-disable-the-windows-subsystem-for-linux-wsl-service

• Microsoft. (2021). Check for updates in Windows 10. https://support.microsoft.com/en-us/windows/check-for-updates-in-windows-10-97fd5b14-11e0-84dd-8587-6c90c2d3dd6d