How to Block Port 135 on Windows 11 Using Windows Firewall?

Blocking Port 135 on Windows 11 using Windows Firewall

Port 135, also known as the epmap port, is a remote procedure call (RPC) endpoint used by Microsoft Windows for various services. While it is necessary for some internal processes, it can also be a potential security risk if left open to external connections. This article will guide you through the process of blocking port 135 on Windows 11 using the built-in Windows Firewall.

Understanding Ports and Windows Firewall

Before diving into the specifics of blocking port 135, it is essential to understand the basics of ports and firewalls. Ports are communication endpoints used by networked applications to send and receive data, and they are identified by unique numbers. A firewall is a security system that monitors and filters incoming and outgoing network traffic, based on predetermined security rules.

 # An example of a firewall rule blocking port 135
 

 <rule>
 <description>Block port 135</description>
 <protocol>TCP</protocol>
 <localport>135</localport>
 <action>block</action>
 </rule>
 

Checking Current Port Status

To verify whether port 135 is currently open on your Windows 11 system, you can use a variety of tools, such as the built-in netstat command or third-party applications like Nmap. If the port is open, it is crucial to take appropriate action and block it to enhance your system's security.

Blocking Port 135 with Windows Firewall

To block port 135 using the Windows Firewall, follow these steps:

1. Press the Windows key + I to open the Settings app.
2. Click on Privacy & Security and then select Windows Security.
3. In the left-hand menu, click on Firewall & network protection and then select Advanced settings.
4. In the Windows Defender Firewall window, expand the Inbound Rules section and click on New Rule.
5. Select the Port option and click Next.
6. In the Specific local ports field, enter 135 and select TCP as the protocol. Click Next.
7. Choose the Block the connection option and click Next.
8. Select when the rule should apply and click Next.
9. Name the rule Block port 135 and provide a description, such as Prevents incoming connections on port 135. Click Finish.

Testing the Block

After creating the new firewall rule, it is crucial to test whether port 135 is now successfully blocked. To do this, use a tool like Nmap or netstat to confirm that the port is no longer open to external connections.

References

• TCP Port 135
• Windows Firewall
• Nmap