How to Protect Remote Desktop Connection on Windows Server 2022 Using Firewall?

Remote Desktop Protocol (RDP) is a vital tool for managing Windows Server 2022 remotely. While it offers great convenience, it is also a frequent target for cyberattacks. Securing RDP access is critical to protecting your server from unauthorized access and data breaches. Using Windows Firewall, you can create a robust line of defense against potential threats.

This article outlines practical steps and best practices for securing RDP connections on Windows Server 2022 using Windows Defender Firewall.

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Why Secure RDP with a Firewall?

RDP enables administrators and users to connect to servers remotely. However, leaving RDP exposed without adequate safeguards can lead to:

• Brute-force attacks, where attackers repeatedly attempt to guess login credentials.
• Unauthorized access by exploiting weak passwords or vulnerabilities.
• Malware and ransomware attacks, which can be deployed via unsecured RDP connections.

A properly configured firewall filters incoming and outgoing traffic, ensuring that only authorized users can access the server.

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Steps to Secure RDP with Windows Firewall

Step 1: Access Windows Defender Firewall

1. Log in to your Windows Server 2022 as an administrator.
2. Open Server Manager, click on Tools, and select Windows Defender Firewall with Advanced Security.

This interface allows you to manage inbound and outbound traffic rules.

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Step 2: Enable the RDP Firewall Rule

To allow Remote Desktop connections, ensure the corresponding firewall rule is enabled.

1. In the Windows Defender Firewall interface, click on Inbound Rules.
2. Locate the Remote Desktop (TCP-In) rule.
3. If it’s disabled, right-click on it and select Enable Rule.

This step ensures that your server accepts RDP connections over the default port (3389).

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Step 3: Restrict RDP Access by IP Address

Limiting access to specific IP addresses helps block unauthorized users from attempting to connect to your server.

1. Right-click the Remote Desktop (TCP-In) rule and choose Properties.
2. Navigate to the Scope tab.
3. Under Remote IP address, select These IP addresses and click Add.
4. Add trusted IP addresses or ranges that are allowed to connect.

This setup ensures that only specified IPs can access your server via RDP.

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Step 4: Change the Default RDP Port

RDP uses port 3389 by default, making it a known target for attackers. Changing this port to a non-standard one adds an extra layer of security.

Steps:

1. Open the Registry Editor by typing regedit in the Start menu.
2. Navigate to:
   HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp.
3. Locate the PortNumber key, modify it, and set a new port (e.g., 3390).
4. Update the firewall rule to allow traffic through the new port:
   • Create a new inbound rule in Windows Firewall for the selected port.

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Step 5: Implement Network Level Authentication (NLA)

Network Level Authentication requires users to authenticate before establishing a remote session. This reduces the server's exposure to potential attackers.

How to Enable NLA:

1. Open System Properties.
2. Go to the Remote tab.
3. Select Allow connections only from computers running Remote Desktop with Network Level Authentication (NLA).

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Step 6: Enable Logging for RDP Connections

Monitoring and logging connection attempts help identify and address potential threats.

Enable Firewall Logging:

1. In the Windows Defender Firewall with Advanced Security, click Monitoring.
2. Enable logging to capture successful and failed connection attempts.
3. Review logs regularly at:
   C:\Windows\System32\LogFiles\Firewall\pfirewall.log.

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Step 7: Disable Unnecessary RDP Features

Disabling unused features minimizes vulnerabilities. For example, clipboard and printer redirection can be exploited in attacks.

Steps:

1. Open Group Policy Editor (gpedit.msc).
2. Navigate to:
   Computer Configuration > Administrative Templates > Windows Components > Remote Desktop Services > Remote Desktop Session Host > Device and Resource Redirection.
3. Disable unnecessary features such as Clipboard Redirection or Printer Redirection.

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Best Practices for Enhanced Security

1. Use a VPN: Require users to connect through a Virtual Private Network (VPN) before accessing RDP. This adds an encryption layer to secure the connection.
2. Enable Two-Factor Authentication (2FA): Use tools like Microsoft Remote Desktop Gateway or third-party solutions to integrate 2FA with RDP.
3. Regularly Update Windows Server: Keep your system updated with the latest patches to mitigate vulnerabilities.
4. Enforce Strong Password Policies: Ensure all accounts use complex passwords to thwart brute-force attacks.
5. Disable RDP When Not in Use: Turn off RDP if it's not actively required.

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Monitoring and Auditing

Regular monitoring of RDP activities and firewall rules helps maintain a secure environment.

• Review Logs: Check event logs in the Event Viewer for unusual login attempts.
• Audit Rules: Periodically verify firewall rules to ensure they align with your security policies.
• Detect Anomalies: Use intrusion detection systems (IDS) to identify and respond to suspicious activities.

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Common Mistakes to Avoid

1. Leaving RDP Accessible to All IPs: Always restrict access to trusted IP ranges.
2. Neglecting Updates: An outdated server is vulnerable to known exploits.
3. Relying Solely on Default Settings: Customize firewall and server settings for optimal security.
4. Weak Passwords: Enforce strong password policies to prevent unauthorized access.

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Conclusion

Protecting RDP connections on Windows Server 2022 is crucial to maintaining server security and preventing unauthorized access. Configuring Windows Defender Firewall effectively—by enabling RDP rules, restricting IP access, and customizing port settings—provides a solid defense against potential threats.

Pair these measures with additional security practices like network-level authentication, VPNs, and regular updates to create a multi-layered security strategy. Proactive management and consistent monitoring ensure that your RDP setup remains secure and reliable for your administrative needs.