This computer can’t connect to the remote computer

First of all, check that the remote computer is accessible over the network and the Remote Desktop port (TCP 3389) is responding. You can check port availability using:

1. Telnet client:

   telnet rdp_server_name1 3389

2. PowerShell 4.0 and higher:

   Test-NetConnection rdp_server_name1 -Port 3389 -InformationLevel Quiet

   

3. PowerShell all versions:

   New-Object System.Net.Sockets.TcpClient).Connect(‘rdp_server_name1’, 3389)

If port 3389 is unavailable, you should check that Remote Connections is enabled on the remote server (Right click on Start button-> System -> Remote settings -> Allow remote connections to this computer).

If Remote Desktop is enabled, next you should to check setting, which determines the maximum number of simultaneously connection to a Remote Desktop. Open tsadmin.msc snap-in (Administrative tools -> Remote Desktop Services -> Remote desktop Session Host Configuration). Click on RDP-TCP properties and check the value of Maximum connections property in Network Adapter tab.

Another possible cause of the RDP error may be a high level of security, which is not supported by older versions of the RDP client.

In this case on RDP-Tcp Properties dialog box open General tab and change Security layer from default Negotiate to less secure RDP Security Layer.

Tip. Snap-in tsadmin.msc and RDP-Tcp Properties dialog box are missing in Windows Server 2012/2012 R2. But you can configure Remote Desktop setting using local group policy editor (gpedit.msc). The necessary policies are located in the following section: Local Computer Policy -> Computer Configuration -> Administrative Templates -> Windows Components -> Remote Desktop Services -> Remote Desktop Session Host.

• RDP security level can be specify using policy named Require user of specific security layer for remote (RDP) connections. Enable this policy and in dropdown select RDP Security level.

  

• Maximum number of RDP connection can be specified in section Connections using policy Limit number of connections. Set unlimited connection by specify 999999 in the option RD Maximum Connections allowed

  

Go back to your client PC and try to start new RDP Session. The connection should be established successfully.

本文转自学海无涯博客51CTO博客，原文链接http://blog.51cto.com/549687/1931733如需转载请自行联系原作者

520feng2007