Saturday, November 13, 2010

Linux: Setup SSH To Tunnel VNC Traffic Though Internet

SkyHi @ Saturday, November 13, 2010
I have UNIX workstation and Linux server at work and Ubuntu desktop at home. It is recommended that I use ssh tunnel the VNC protocol for secure communication. How do I access my UNIX workstation desktop here at home over the Internet using ssh?

VNC can be accessed over the Internet using ssh protocol. This will improve security as traffic will be encrypted.

Sample Setup
 +----------------+                   +-----------------+
 | Laptop @ Home  |---> Internet ---> | UNIX PC @ Work  |
 +----------------+                   +-----------------+
                                       vncserver port 5901

 +----------------+                   +-----------------+
 | Laptop @ Home  |---> Internet ---> | Router/firewall |
 +----------------+                   | port forwarding |
                                            | ssh/tcp22
                                          //   \\
                                          /      \
                                       | UNIX/Linux /OS X|
                                       | at work         |
                                       vncserver @ port 5901
Your work pc may be directly connected to the Internet. Otherwise most offices have a router and firewall installed. You need to make sure your firewall allows port forwarding for TCP port 22 to your UNIX / OS X / workstation or server called It works as follows:
 | SSH Client |-------> Internet ssh connection with encryption
 | with       |                         |
 | vncviewer  |                         |
 +------------+                         |
                             | SSH server at port 22  |
                             | Vncserver at port 5501 |
You connect from your local ssh client (localhost) to your ssh server ( installed at your work UNIX pc with port forwarding at router / firewall level. I'm assuming that port forwarding is correctly configured at your office. Now, open the terminal and type the following command:
ssh  -N -f -L 5000:localhost:5901 vivek@pc22.nixcraft.i
The above command will start an ssh connection to and also listen on port 5000 on localhost and forward vnc connection to port 5901 on Usaully local and remote port numbers are same to avoid confusion:
ssh  -N -f -L 5901:localhost:5901 vivek@pc22.nixcraft.i
Now, you can use vncviewer at your home as follows:
vncviewer localhost:5901
You can also use GUI tool and set VNC server location to localhost:5901

Fig.01: Setup ssh to tunnel VNC traffic over the Internet
Fig.01: Setup ssh to tunnel VNC traffic over the Internet

Once connected you will get desktop login windows or last session window as follows:
Fig.02: VNC in action and more secure using SSH
Fig.02: VNC in action and more secure using SSH