Setup Remote Desktop on CentOS / Red Hat


This is a modified repost for my own documentation from 7ota

This tutorial deals with setting up a machine for remote desktop access just like an RDP connection to a windows system but using VNC.

First install the VNC Server portion:

yum install vnc-server

To install VNC client:

yum install vnc

Open ports 5900 and 5901 on the firewall. If you want more than one VNC sessions to occur simultaneously, then open ports for those in your firewall. Say you want four simultaneous sessions. Then you would want to open ports 5901, 5902, 5903, and 5904. You may open ports in GUI or via command line.

Now make sure all users have their own .vnc directory in their home directory. For example, ‘testuser’ should have a /home/testuser/.vnc/ directory. If not, create one using

mkdir /home/testuser/.vnc/

Now setup VNC passwords for each user you want to allow VNC for. For example. if you want user ‘testuser’ to be able to VNC, log in as ‘testuser’ and run command

vncpasswd

It will ask you to enter and verify your password. Remember, each user needs to set up their own password with this command. It will store password in /home/testuser/.vnc/passwd file.

Check to see if you have xstartup file in /home/testuser/.vnc/ and if not, create one using

vim /home/testuser/.vnc/xstartup

And make sure it looks like this:

#!/bin/sh
# Uncomment the following two lines for normal desktop:
unset SESSION_MANAGER
exec /etc/X11/xinit/xinitrc
[ -x /etc/vnc/xstartup ] && exec /etc/vnc/xstartup
[ -r $HOME/.Xresources ] && xrdb $HOME/.Xresources
xsetroot -solid grey
vncconfig -iconic &

xterm -geometry 80×24+10+10 -ls -title “$VNCDESKTOP Desktop” &
startx &
exec gnome-session &

I chose GNOME because I use it on CentOS. If you prefer KDE, just change gnome-session to kde-session. Also, you have to make this file executable, using the following

chmod u+x /home/testuser/.vnc/xstartup

If you do not make this executable, and once VNC is all setup, you may only get a gray screen with a big black mouse pointer. If you make this file executable, this problem should not occur.

Another reason you may get this gray screen is when the character encoding of the file may not be what the scripts are expecting. To remedy this situation, make sure you use files created and modified on Linux. I had the same problem when I created a file on Windows and downloaded it in Linux. When I created the file in Linux, the problem went away.

Now, as root, you need to edit one file

vim /etc/sysconfig/vncservers

And make sure it has the following lines:

VNCSERVERS="1:testuser 2:otheruser 3:moreuser"
VNCSERVERARGS[1]=”-geometry 1024×768 -depth 16″
VNCSERVERARGS[2]=”-geometry 800×600 -depth 16″
VNCSERVERARGS[3]=”-geometry 1024×768 -depth 16″

What we are doing here is setting up three VNC sessions for three users: testuser, otheruser, and moreuser. Add as many users as you want here. Remember, also open ports in firewall for each VNC session you open.

Be careful. After first installing VNC server, VNCSERVERARGS[1] will not look like this and would probably have flags set so that it doesn’t listen on network. You have to make sure your file looks like what has been shown above. Be careful that -depth is at least 16, not 8. Otherwise it may not work properly. Of course, you may set an appropriate screen resolution, not necessarily what has been set above.

Now you are ready to start VNC server as root.

service vncserver start

To make sure VNC starts up whenever the computer starts, do the following

chkconfig vncserver on

It should give you an OK for all VNC sessions you added in /etc/sysconf/vncservers. You will connect using your VNC client using the following address:

yourhostname :1

or you could use an IP address

192.168.168.100 :1

Where :1 is the number chosen for the user in /etc/sysconf/vncservers. When asked, enter password for that user. The benefit of this method is you do not need to enable auto login to be able to use VNC.

I have to thank the following for helping me learn and also write about this issue: Tutorial: VNC; Set up the VNC server in Fedora;

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