Troubleshooting RDP

In some situations, you might not be able to connect to your Google Compute Engine Windows instance via RDP. This problem can be due to any number of network or configuration errors. This page describes a number of tips and approaches to troubleshoot and resolve common RDP issues.

Ensure the instance is online and ready

The status of your Windows instance is available via serial console. Connect to the read only or interactive serial console to see that the instance is ready.

  • Serial Console 1 (read only)

    1. Open your Windows instance from the VM instances page in Cloud Console.
    2. Click the dropdown arrow next to Connect to serial console, and select Serial port 1, or the gcloud SDK command below:

      gcloud compute connect-to-serial-port [INSTANCE_NAME] --port 1
    3. Confirm that the instance has started, and has attempted to run startup scripts.

      Booting from Hard Disk 0...
      GCEWindowsAgent: GCE Agent Started (version x.x.x@x)
      GCEMetadataScripts: No startup scripts to run.
  • Serial Console 2 (interactive)

    1. Enable interactive access on the serial console via the VM instance page , or the gcloud SDK command below:

      gcloud compute instances add-metadata [INSTANCE_NAME]^
    2. Open your Windows instance from the VM instances page in Cloud Console.

    3. Click the dropdown arrow next to Connect to serial console, and select Serial port 2. Alternatively, you can run the following gcloud SDK command:

      gcloud compute connect-to-serial-port [INSTANCE_NAME] --port 2
    4. Confirm that the cmd process is available to use.

      Screenshot of the SAC cmd command being available

Check your VPC firewall rules

Google Compute Engine automatically provisions new projects with a firewall rule that allows RDP traffic. If you have an existing project, or have modified the configurations, the default firewall rule that permits RDP might not exist. Confirm that a rule allows RDP traffic to connect to the network that your affected instance is on.

To check if the default-allow-rdp firewall rule exists on your project, check the Firewall rules page, or run the following gcloud SDK command:

gcloud compute firewall-rules list

To create a new rule if one does not exist, create a rule with the following command:

gcloud compute firewall-rules create allow-rdp --allow tcp:[PORT_NUMBER]

Check your Windows instance password

Each Google Compute Engine Windows instance must have a local password set if it is not already on a domain or custom image. Confirm you have the correct password set by connecting to the Windows SAC through the gcloud command-line tool or GCP Console.

If you have problems connecting, try creating or resetting the password on the Windows instance.

Verify the external IP address

Ensure that you're connecting to the correct external IP address for the instance. View the IP for the instance from the VM instance page or by using the following gcloud SDK command:

gcloud compute instances list

Check the OS configuration

If the environment and configurations for the instance are correct, the operating system on the instance might be misconfigured. You can use the interactive serial console to connect to the instance and troubleshoot the problem.

Connect to the instance through one of the available command line methods, and run the following commands to ensure that the instance is accepts connections:

  1. Check to see that the 'Remote Desktop Service' is running:

    • Command: net start | find "Remote Desktop Services"
    • Pass: Remote Desktop Service
    • Fail: (Remote Desktop Service missing from output)
    • Solution: net start "Remote Desktop Services"
  2. Check that Remote Connections are enabled:

    • Command: reg query "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server" /v fDenyTSConnections
    • Pass: fDenyTSConnections REG_DWORD 0x0
    • Fail: fDenyTSConnections REG_DWORD 0x1
    • Solution: reg add "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server" /f /v fDenyTSConnections /t REG_DWORD /d 0
  3. Ensure that the Windows firewall has Remote Desktop Connections enabled:

    • Command: netsh advfirewall firewall show rule name="Remote Desktop -User Mode (TCP-In)"
    • Pass: Enabled:Yes, Direction: In, Profiles: Public, Grouping: Remote Desktop, LocalIP: Any, RemoteIP: Any, Protocol:TCP, LocalPort: 3389, RemotePort: Any, Edge traversal: No, Action: Allow

    • Fail: (unexpected results, such as enabled = No)

    • Solution: netsh firewall set service remotedesktop enable

  4. Check to see what port number is configured for RDP connections on the remote instance:

    • Command: reg query "HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp" /v PortNumber
    • Pass: PortNumber REG_DWORD [PORT NUMBER]
    • Fail: (unexpected port number)
    • Solution: reg add "HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp" /f /v PortNumber /t REG_DWORD /d [PORT NUMBER]

  5. Ensure that connected user account has permissions for remote connections:

    • Command: net localgroup "Remote Desktop Users"
    • Pass: (target local/domain username in resulting list)
    • Fail: (target local/domain username missing)
    • Solution: net localgroup "Remote Desktop Users" /add [DOMAIN\USERNAME]

  6. Verify that your MTU size is no greater than 1460:

    • Command: netsh interface ipv4 show subinterfaces
    • Pass: MTU 1460, MediaSenseState 1, Bytes In 915643107, Bytes Out 681487030, Interface: Ethernet

    • Fail: (MTU is set to larger than 1460)

    • Solution: netsh interface ipv4 set subinterface Ethernet mtu=1460

  7. Ensure that your antivirus/endpoint protection client settings allow for the configured port number and services.

Use your disk on a new instance

If the other troubleshooting steps do not resolve your connection issue, you might be able to delete the existing instance and preserve your persistent disk. Remount the disk to a new instance and make another troubleshooting attempt, or simply recover existing data from the disk.

gcloud compute instances delete [INSTANCE_NAME] --keep-disks=boot
gcloud compute instances create [NEW_INSTANCE_NAME] --disk name=[DISK_NAME]^
boot=yes auto-delete=no
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