Windows RealVNC server not accepting connections

Mike Miller mbmiller+l at
Fri Oct 28 22:06:07 BST 2011

On Fri, 28 Oct 2011, Mike Miller wrote:

> I'm running the latest Free RealVNC server in service mode on a WinXP 
> box and it isn't accepting any connections.  I tried to connect to 
> localhost and I get a dialog box right away saying the connection closed 
> unexpectedly.  I'm not prompted for a password.

I realized that I was allowing connections only from a certain other 
machine on the subnet, and was therefore blocking connections from 
localhost.  I fixed that and then was able to make the connection from 
localhost.  So I guess this is what we see in the event log when WinVNC is 
disallowing a connection (at least if it is from localhost):

SocketManager: unknown listener event: 0

This is still a problem:

> But when I try to connect from a Linux machine on the subnet, it doesn't 
> register anything.  When I use nmap on the Linux box to look at the 
> Windows box, I see that port 5900 is "filtered" rather than "open".
> I was able to use "vncviewer -listen" on the Linux box to receive a 
> connection from the VNC server on Windows.  That worked but only 
> momentarily. It locked up almost right away and then the VNC server 
> crashed on Windows, including the usual Microsoft request to report the 
> error, which I did.

Any ideas?  Why would the server crash after making a connection to a 
listening viewer?

I'm guessing that my problem making a normal connection is due to some 
kind of firewalling problem.  I'm trying to turn all of that off.  It's 
hard to figure out exactly where the problem is, though.


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