Issue Connecting to a PC via Remote Desktop Connection from Branch Office VPN

Question

We have two sites with Windows 11 PCs, and some remote users connect to a few machines at Office A using Remote Desktop Connection to access older software.

One specific machine allows connection via VPN, but connections through the branch office VPN fail. This issue affects only one machine, and it appears to have the same settings as the others. The following troubleshooting steps have been taken:

• Remote Desktop settings disabled and re-enabled.
• Verified that users are added to the Remote User List.
• Changed the IP address assigned to the machine.
• Confirmed the machine responds to pings via the branch office VPN.
• Tested with ESET EndPoint Antivirus turned off.
• Tested with the Windows firewall turned off.
• Attempted connections from multiple PCs.
• Remote PCs can browse shares on the host PC.
• Telnet to the host on port 3389 also fails to connect.

Answer 1

Hello,

You may consider the below steps to perform additional checks:

1. Run CMD netstat -an | find "3389" to check if RDP is actually listening on port 3389. If you don't see LISTENING, try restarting the RDP service.
2. Check if the port has been changed in the registry: Change the listening port in Remote Desktop | Microsoft Learn
3. Since file sharing works but RDP doesn't, check if any VPN configuration that might be blocking RDP traffic from the branch office.
4. Check Windows Logs for RDP Failures: Remote Desktop Services Events (by Role Service) in Windows Server 2008 R2 | Microsoft Learn
5. If Network Level Authentication (NLA) is enabled, try disabling it.

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Answer 2

Thank you for your suggestions after investigating this further I found that this issues was an IDS policy in the ESET antivirus software installed on the machine I was trying to connect to.