Microsoft KB Archive/816763

= You may receive an &quot;Unable to connect to&quot; error message when you try to debug a process through a firewall on a remote computer =

Article ID: 816763

Article Last Modified on 6/1/2007

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APPLIES TO


 * Microsoft Visual Studio 6.0 Enterprise Edition
 * Microsoft Visual Studio .NET 2002 Academic Edition
 * Microsoft Visual Studio .NET 2002 Enterprise Architect
 * Microsoft Visual Studio .NET 2002 Enterprise Developer
 * Microsoft Visual Studio .NET 2002 Professional Edition
 * Microsoft Visual Studio .NET 2003 Academic Edition
 * Microsoft Visual Studio .NET 2003 Enterprise Architect
 * Microsoft Visual Studio .NET 2003 Enterprise Developer
 * Microsoft Visual Studio .NET 2003 Professional Edition

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SYMPTOMS
When you try to debug a process through the firewall on a remote computer, you may receive one of the following error messages:  Error message 1:

Unable to connect to. The remote machine is not responding.

Note The placeholder  is a placeholder for the Internet Protocol (IP) address of the remote computer where you are trying to debug the process. Error message 2:

Unable to connect to. MSVCMON is not running on the remote machine.

Note The placeholder  is a placeholder for the name of the remote computer where you are trying to debug the process.



CAUSE
The Remote Debug Monitor (MSVCMON) process communicates with a fixed-port number from 2064 through 2079. If the firewall blocks the ports from 2064 through 2079, the MSVCMON process fails.



RESOLUTION
To resolve this problem, do not block the ports on the firewall from 2064 through 2079. If the ports from 2064 through 2079 are blocked, a system administrator can unblock the ports.



STATUS
This behavior is by design.



MORE INFORMATION
You can use the &quot;telnet&quot; command-line utility to verify that a port is blocked. At the command prompt, type the following command:

telnet  2064

Note The placeholder  is a placeholder for the IP address of the remote computer.

If port 2064 is not blocked, you receive the following message:

connected to the remote system

If port 2064 is blocked, you receive the following error message:

Connect failed

