This applies to all versions of Windows 2003 and Windows 2008 and also to Vista and XP Professional. This problem normally occurs to our client with Dedicated Server hosting. So I thought I will create a check list to make their hosting service a bit easy.
Yes, you will need physical access to the machine to check this, it is obvious that you will not be able to check this problem unless you have remote access to the server. These steps can only be performed if you have physical access to the dedicated server or through a Keyboard-Video-Mouse [KVM]. So there we go:

* First thing that you need to check is whether the Remote Desktop Console [RDC] is enabled on your server.
Go to Desktop >> My Computer >> Properties >> Remote Tab
Check the box for “Enable Remote Desktop on this computer” and click OK.

* If the above option is enabled then make sure that the user which you are using to connect the server remotely is added in the “Remote Desktop users” group. Administrators are normally added in the group. This can be confirmed from with the steps below:
Go to Desktop >> My Computer >> Mange
Expand Local Users and Group >> Select Group.
Double click on “Remote Desktop Users” Group and make sure that the user is added in here.

* If both the above settings are correct then you need to make sure that TCP port 3389, which is the default port for RDC is enabled in the firewall of the machine that is used to RDP the server. Vise a verse make sure that the server firewall also has this port added in the exception. The best way to check this is:

First make sure that the server listens to telnet, try telnet of any other port which you are sure is working on the server like port 80 or 25. The command would be:

TELNET ip_address 25

If this works then try telnet on port 3389.

TELNET ip_address 3389

* If the telnet is not working then there are several possibilities, it can be the firewall on your machine or the firewall on the server tha is blocking the port. It can also be the case that Terminal Server Service did not start for some reasons. Or in a very rare situation it could be that the RDP port has been changed by some one. We will rectify all the possibilities one by one:

* Check the firewall on your machine or just shut the firewall down and then try the telnet again.

* If you have Windows Firewall then make sure that Remote Desktop is added in Exception.
Goto Start >> All Programs >> Control Panel >> Windows Firewall
If you have a third party firewall your dedicated server then just disable it and try the telnel option.

* If that is not the firewall issue make sure that Terminal Server Service is set to Automatic and is running. This server depends on Remote Procedure Call Service and you get errors while starting the server and you will need to trouble shoot the problem. If the server is terminating unexpectedly then make sure that the Hardware profile of the server is set to “Enable”:

* Sometimes client with Windows Dedicated Hosting package change the RDP port of their server and forget it, the steps below can be used for checking the RDP port as well as changing it as well, these steps will require to make changes in Registry hence it is recommended to backup the registry before following these steps:

Goto Start >> Run
Type: regedit to open the registry editor MMC
Expand to the Key:
[HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlTerminal ServerWinStationsRDP-Tcp]
Modify the value for Key “PortNumber”
Change Base to Decimal

Change Value data to the port your desire for your Dedicated Server
Click OK
Reboot the Machine.

Once the machine is online you will have to define your the port to connect your Dedicated Server remotrly
ip_address:port_number
10.10.10.52:3362

1] Remote Assistance uses Windows XP/2003 Terminal Services to share desktop and other resources between two PCs.

Terminal Services - It is a way of using RDP (Remote Desktop Protocol), which allows users to connect to their Windows XP desktop or a dedicated server (Terminal Server) combining with VPN (Virtual Private Network) with the help of which users can connect to their office network remotely and work with their applications.

Virtual Private Network – Creates a secure connection between private networks.

In a *Remote Assistance Session* -

Both users must be present at their respective PCs and must agree to establish a connection.

Remote Assistance is designed for peer-to-peer use by Windows users.

In which a Novice (asking for help) from a Expert (technician, or friend, or helpdesk, or vendor). To have a successful Remote Assistance both users must have active Internet connections or be on the same local area network, and neither of them should be blocked by firewalls.

2] The Remote Desktop service is available as part of Windows XP Professional Edition. This service allows you to take control of the remote computer without requesting for access.

To do this you need to have administrator login details of the machine on which you will be doing Remote Desktop. Once logged in you will have complete control of the Remote computer.

To enable Remote Desktop or Remote Assistance services:

Right-click on My Computer and choose Properties. Click on the Remote tab >> Check both Remote Assistance and Remote Desktop >> Apply >> Ok