Joseph Herlant
version 1.0.0, 2014-07-11 : Initial version

1. Introduction

This procedure has been tested on a CentOS 6.5 environment, so it could differ from yours if you’re not using the save OS or version.

Here we are installing and configuring a vnc server on a server which IP is:

As using VNC implies using an X server, you’ll need to have and X11 environment available. You can install one with yum groupinstall -y Desktop which will provide you a Gnome Desktop environment.

You will also need to have some users to use VNC with. For this example here, we have created the grumpy and sleepy users (simply using useradd -m <username>) and changing their password (using passwd <username>).

This procedure explains how to configure an UNENCRYPTED vncserver. For more security in a production environment, you could consider using an ssh tunnel to connect to it and so retrict the vnc server to listen only to localhost.

2. Server side installation and configuration

First things first, install the vnc server package:

sudo yum install -y tigervnc-server

Then configure it by editing the /etc/sysconfig/vncservers file which should, in the end, look like this:

VNCSERVERS="1:sleepy 2:grumpy
VNCSERVERARGS[1]="-geometry 800x600 -nolisten tcp"
VNCSERVERARGS[2]="-geometry 800x600 -nolisten tcp"

Then configure iptables to let the ports 5901 and 5902 in our case (if se had a 3rd one, it would be 5903) listening only on the network (if you only have one administration gateway, you should think about a more restrictfull limitation) as root:

iptables -I INPUT 5 -p tcp -m tcp -m multiport --dports 5901:5902 -s -j ACCEPT
# Don't forget to save and restart
service iptables save
service iptables restart

Then, you need to su to each of your users to set their vnc passwords using the vncpasswd command, which will create a $HOME/.vnc/passwd password file.

sudo su - sleepy
sudo su - grumpy

Once it’s done, you could start correctly your vncserver service as root:

service vncserver start
chkconfig vncserver on

3. Client side configuration

On client part, you need to install the vnc client. Here we are using tigervnc package that provides vncviewer, so we’ll first install it. Note that you’ll need and x client for this to work, so if not already done, you’ll certainly need to do a yum groupinstall -y Desktop to get a Gnome.

sudo yum install -y tigervnc

You now can either use the graphical menu provided (in the "Internet" menu group of gnome) or use the command line (you need to set the correct USER to connect vnc configuration) like this:

USER=sleepy vncviewer
USER=grumpy vncviewer