How to connect VNC without SSH?

notooth · 01-26-2021, 05:58 PM

Hello,

I successfully connected to a VNC server through an SSH tunnel, but it didn't let me do that without SSH. Is there a way to disable SSH and connect directly to the VNC server?

wpeckham · 01-26-2021, 07:40 PM

It is EASY, the default VNC server/client setup did not use SSH originally. The problem is that you would have to have control of both ends. If the server end is set up to REQUIRE ssh, then the VNC client MUST use SSH to reach it. Do you have control of both ends?

notooth · 01-27-2021, 02:01 AM

Yes, I have control of both ends. What should I do?

Turbocapitalist · 01-27-2021, 02:05 AM

You should still use SSH, since if the raw VNC interface gets exposed to the net, intruders will find it and use it to quickly and easily enter your system.

notooth · 01-27-2021, 07:25 AM

It's just a connection between a host and a local VM.

berndbausch · 01-27-2021, 07:58 AM

Does the VM allow connection requests to the VNC ports? Some distros like Centos or Fedora block all ports except SSH by default.

wpeckham · 01-27-2021, 09:13 AM

Quote:

Originally Posted by wpeckham

It is EASY, the default VNC server/client setup did not use SSH originally. The problem is that you would have to have control of both ends. If the server end is set up to REQUIRE ssh, then the VNC client MUST use SSH to reach it. Do you have control of both ends?

It suddenly occurs to me to ask: WHY would you want to eliminate ssh from the vnc connection?
I mean: it is working as configured, and that IS the preferred method. Why break it just to eliminate SSH?

notooth · 01-27-2021, 09:31 AM

Quote:

Originally Posted by berndbausch

Does the VM allow connection requests to the VNC ports? Some distros like Centos or Fedora block all ports except SSH by default.

I don't know. It's Debian 10.7 with default installation on the VM.

berndbausch · 01-27-2021, 05:14 PM

Quote:

Originally Posted by notooth

it didn't let me do that without SSH. Is there a way to disable SSH and connect directly to the VNC server?

It occurs to me that we don't know what exactly happens. How do you try to connect, which IP address and port are you using, and what are the symptoms (e.g. error message)?

Also how did you create the tunnel.

To connect directly, use the server's IP address followed by a colon and the display number. Instead of the display number, you can use the port, which is normally 5900+DISPLAYNUMBER.

As far as I know, Debian doesn't block network ports by default.

notooth · 01-28-2021, 02:28 AM

This is how I successfully used the tunnel:

Code:

$ ssh -L 5901:localhost:5901 notooth@10.0.0.5
$ vncviewer localhost:5901

This is how I failed to use a direct connection:

Code:

$ vncviewer 10.0.0.5:1
Error: unable connect to socket: Connection refused (61)

andre@home · 01-28-2021, 03:40 AM

Is the port you tried to use without SSH open in the firewall.... ?

wpeckham · 01-28-2021, 08:38 AM

Quote:

Originally Posted by notooth

This is how I successfully used the tunnel:

Code:

$ ssh -L 5901:localhost:5901 notooth@10.0.0.5
$ vncviewer localhost:5901

This is how I failed to use a direct connection:

Code:

$ vncviewer 10.0.0.5:1
Error: unable connect to socket: Connection refused (61)

Check to see if your vncserver is listening on the proper port for a direct connection. Next check to see if your firewall is runnign and blocking that port.

notooth · 01-28-2021, 07:40 PM

There is no firewall on the VM. The vncserver listens to the port 5901.

michaelk · 01-28-2021, 08:14 PM

Quote:

Originally Posted by notooth

This is how I successfully used the tunnel:

Code:

$ ssh -L 5901:localhost:5901 notooth@10.0.0.5
$ vncviewer localhost:5901

This is how I failed to use a direct connection:

Code:

$ vncviewer 10.0.0.5:1
Error: unable connect to socket: Connection refused (61)

Have you tried

vncviewer 10.0.0.5:5901

berndbausch · 01-29-2021, 01:51 AM

Quote:

Originally Posted by notooth

There is no firewall on the VM. The vncserver listens to the port 5901.

Which address though? Post the output of ss -nltp | grep 5901.