Unable to connect to remote computers

Problem

Unable to establish connections to remote computers from the Desktop Central server.

Cause

The inability to connect to remote computers from the Desktop Central server could be because of one or more of the following reasons:

• Communication is blocked by the firewall in the computer in which the Desktop Central server is installed. To confirm if this is one of the reasons, try connecting to the Desktop Central server from a computer, to which you want to establish a remote connection, using Telnet. Execute the following command in the Command Prompt window:

  telnet<space>Desktop_Central_Server_IP<space>Remote_Control_Gateway_Port

  For example, telnet 192.168.110.23 8443. If you are unable to connect, you can be sure that the firewall is blocking communication between the Desktop Central server and agent.
• No agent is installed in the computer to which you want to establish a remote connection
• Unable to access the target computer
• Issues related to browsers. For example, absence of JAVA plug ins and Active X controls

Resolution

Identify the problem and follow the relevant resolution from the list given below:

Communication blocked by firewall

The communication required to connect remotely to a computer could be blocked by either of the firewalls mentioned below:

Firewall in the Desktop Central Server

The firewall running in the machine in which the Desktop Central server is installed may block requests. To resolve this issue, add the following:

• Port 8443 to the exceptions list of the firewall
• 'Remote Assistance' to the exceptions list of the Windows firewall

Firewall between Desktop Central Server and LAN Agents

Consider a scenario where you are managing computers in your remote offices from your head office and you use "Direct Communication" between the LAN Agents and Desktop Central Server. If you have a firewall between the Desktop Central Server and the LAN Agents, you should configure the firewall to enable remote administration:

• For Remote Administration open the TCP port 135.
• For File and Printer Sharing open the ports TCP 139, TCP 445, UDP 137, UDP 138.

DC Agent is not installed
Check if the Desktop Central Agent is installed in the Client Computer. If not push and install the agent in the client machine from SoM. The steps include:

From the UI

1. Select the Admin tab to invoke the Admin page.
2. Click the Scope of Management link available under Global Settings. This invokes the Scope of Management page.
3. The Computers tab is selected by default showing all the computers that have been added already.
4. Select the computers for which the Agent has to be installed and click Install Agent. Click OK to confirm

Installing Agents Manually

You can also install the agents manually, by downloading the agent program from the SoM page:

For Local Office

Click the Download Agent link and select Local Agent (LAN) to download the agent installable.

For Remote Office

Click the Download Agent link and select the corresponding Remote Office name to download the agent installable.

Double-click the msi file to install the agent manually.

Problems accessing the target computers

• Check if the selected computer is down. If so, make it up and running.
• Specify and use the IP Address of the computers to connect, if you have computers with same name in two different domains/workgroups
• Verify whether the IP Address of the selected computer is shown correctly In case there is a Virtual IP, you will need to remove the virtual IP Address for Remote Control. The steps would include:
  1. Select the Tools tab and go to Remote Control.
  2. Click on Edit IP icon under the IP Address field.
  3. Remove the virtual IP address/ correct the IP address in the IP Address text field.
  4. Save Changes and Login afresh.
• Enable "File and Printer Sharing for Microsoft Networks" in the network adapter of the client computers.
  The steps are as follows:

1. Select Start --> Settings --> Network Connections.
2. Right-click the network connection and select Properties.
3. In the connection properties dialog, select the General tab.
4. Select the "File and Printer Sharing for Microsoft Networks" and click OK.
5. If you do not find this option, click Install button.
6. In the network component type, select Service and click Add.
7. Select File and Printer Sharing for Microsoft Networks and click OK.
8. Click Close to exit the properties dialog

Browser issues

• Ensure your browser has Java plug-ins.
• Enable ActiveX Controls in Internet Explorer.

Applies to: Remote Desktop Management, Troubleshoot Remote Desktop, Remote Desktop Connection problems

Keywords: Remote Desktop, Manage Remote computers, Troubleshoot Remote machines

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