Install vncserver on Ubuntu 18.04 desktop

In this guide, we will be using tigervnc server

Install the vncserver
$ sudo apt update; sudo apt install tigervnc-standalone-server tigervnc-xorg-extension -y

Setup a password for vncserver
$ vncpasswd

Once you have provided the password, make sure a passwd file is created
$ ls ~/.vnc/
passwd

Run below command to put some settings in ~/.vnc/xstartup, so that gnome will be started when vnc is used
$ cat > ~/.vnc/xstartup <<EOF
#!/bin/sh
# Start Gnome 3 Desktop 
[ -x /etc/vnc/xstartup ] && exec /etc/vnc/xstartup
[ -r $HOME/.Xresources ] && xrdb $HOME/.Xresources
vncconfig -iconic &
dbus-launch --exit-with-session gnome-session &
EOF

Press ctrl-d to save the above file

Start a vncserver instance
$ vncserver

List the display to get the port number to connect to, in this example the port number would be 5901, since the display number is 1
$ vncserver -list 

TigerVNC server sessions:

X DISPLAY # PROCESS ID
:1 5375

In the client machine, connect with using vncviewer like below, replacing the x.x.x.x with your server's ip number
$ vncviewer x.x.x.x:5901


To terminate the vnc session, use below command to kill the first instance of the vncserver
$ vncserver -kill :1

Connecting to your machine using vnc

To setup and use vncserver in redhat flavored distro, please follow below steps:

1. Install the package:

   $ sudo yum install tigervnc-server tigervnc

2. Set a password for a user that you want to use to login to the vnc server:

   $ vncpasswd

3. Start the vncserver:

   $ vncserver

4. Check the display number of your newly created vnc session:
   

   $ vncserver -list
   TigerVNC server sessions:
   X DISPLAY #     PROCESS ID
   :1              9168

5. Check the port that your vnc session is using:

   $ sudo netstat -tulpn | grep 9168
   tcp        0      0 0.0.0.0:5901                0.0.0.0:*                   LISTEN      9168/Xvnc
   tcp        0      0 0.0.0.0:6001                0.0.0.0:*                   LISTEN      9168/Xvnc
   tcp        0      0 :::6001                     :::*                        LISTEN      9168/Xvnc

6. Test your vncserver locally (only if you are using GUI, else test it from the other machine with vncviewer installed), using vncviewer (belongs to tigervnc package):
   

   $ vncviewer :1

To connect from a redhat flavored linux distro client:

1. Install the tigervnc package:
   

   $ sudo yum install tigervnc

2. Run the vncviewer: vncviewer :

   $ vncviewer 192.168.0.2:1
   

3. If you are behind firewall, you need to open port 5901 for the client to get through.
4. If firewall is not in your control, you can always use ssh to port forward port 5901 to 5901 in your localhost, by: 

$ ssh -L 5901:localhost:5901 vncserver.ip.address

and in other terminal, run

$ vncviewer localhost:1

Once you are done, you can kill the server by running:

$ vncserver -kill :1