Unable to access server via VNC with firewall turned on in SLES10

Posted on 2007-11-19
Medium Priority
Last Modified: 2013-11-30

Running SLES 10 on my test machine.  Having trouble accessing the server remotely with the firewall turned on.  I have allowed the following services on Network interface (External Zone) 1. SSH 2. Remote administration 3. Remote access to Display manager.  The VNC server is running properly on the server. If I disable the firewall, I can connect without a problem.  What else do I need to do to allow remote access via vnc.  Note;  I can connect via ssh with the firewall turned on.
Question by:Cobraiti

Assisted Solution

gmilhon earned 400 total points
ID: 20316751
The Remote administration and remote access to display manager services aren't the services for VNC. You need a service that allows TCP port 5900. That is the protocol and port that VNC uses, you need to configure this service and allow access to it.
LVL 35

Accepted Solution

ShineOn earned 1600 total points
ID: 20316811
VNC listening ports are usually 5900, 5901, etc. - the http ports are 5800, 5801, etc.

The remote access to display manager is the remote X-server service "xdmcp" which service translates to TCP port 6000-6005 and UDP  port 177.  You shouldn't need to open those unless you're going to use an X session outside the realm of VNC.

If you enable "remote administration" then TCP ports 5801 and 5901 are opened up.  That's all well-and-good if you set up remote VNC sessions only for X session 1.  If you want to use X session 0 (remote desktop) you have to manually open up ports 5800 (html VNC) and/or 5900 (VNC client.)  If you want multiple VNC sessions, you have to have more ports open in that range, but you also have to set it up so X will handle more sessions with VNC "devices."

Hope this helps.  Again, for session zero, in other words whatever the actual system's GUI looks like, interactively, you need the 5800 or 5900 port, not what SuSE Firewall plugs in for "remote administration" which is session 1, 5801/5901.


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