Setting Up VNC Server On Oracle Enterprise Linux 6.7

Setting Up VNC Server On Oracle Enterprise Linux 6.7

VNC stands for Virtual Network Computing, which allows us to access GUI of our server remotely. Though we DBA does our every task by connecting to our server via SSH-TTY tunnel. However in some cases we need to have GUI access of the server to perform certain tasks, which needs a Display. We’ll just need to have VNC Client Application to access it. So in this post we’ll see how to setup VNC Server in easiest way on your Oracle Enterprise Linux 6 / RedHat Enterprise Linux 6, however this is demonstrated on Oracle Enterprise Linux 6.7.


To setup VNC Server, we need to install Packages of VNC Server. We’ll use tigervnc and there are several ways to install these packages, however using yum is always best and preferable because yum itself checks if all dependency packages are present or not and installs missing dependency packages as well.

Note : To perform any administrative operations we’ll always need to switch to root user or optionally sudo can be used.

1. Check if Tiger VNC is installed on your system.

Run below commands to check if VNC Server is installed or not.

[[email protected] ~]# yum list | grep tigervnc

or

[[email protected] ~]# rpm -qa | grep tigervnc

If above commands returns nothing, it means there is no VNC Server installed on the server. So we can proceed with installation now.


2. Before installing check info about Tiger VNC on yum repository.

[[email protected] /]# yum info tigervnc-server
Loaded plugins: refresh-packagekit, security, ulninfo
Available Packages
Name : tigervnc-server
Arch : x86_64
Version : 1.1.0
Release : 24.el6
Size : 1.0 M
Repo : public_ol6_latest
Summary : A TigerVNC server
URL : http://www.tigervnc.com
License : GPLv2+
Description : The VNC system allows you to access the same desktop from a wide
                      : variety of platforms. This package is a TigerVNC server, allowing
                      : others to access the desktop on your machine.

Above are the details of Architecture, Name, Release, Size, License and more.


3. Install Tiger VNC using yum.

[[email protected] /]# yum install tigervnc-server
Loaded plugins: refresh-packagekit, security, ulninfo
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package tigervnc-server.x86_64 0:1.1.0-24.el6 will be installed
--> Processing Dependency: libxshmfence.so.1()(64bit) for package: tigervnc-server-1.1.0-24.el6.x86_64
--> Running transaction check
---> Package libxshmfence.x86_64 0:1.2-1.el6 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

============================================================================================================
 Package                      Arch             Version               Repository                 Size
============================================================================================================
Installing:
 tigervnc-server              x86_64           1.1.0-24.el6          public_ol6_latest          1.0 M
Installing for dependencies:
 libxshmfence                 x86_64           1.2-1.el6             public_ol6_latest          5.6 k

Transaction Summary
============================================================================================================
Install 2 Package(s)

Total download size: 1.0 M
Installed size: 2.6 M
Is this ok [y/N]:

Once yum completes with searching installation package on Yum repository, yum prompts for Yes / No option, type Y for yes selection.

Is this ok [y/N]: y
Downloading Packages:
(1/2): libxshmfence-1.2-1.el6.x86_64.rpm                                              | 5.6 kB       00:00
(2/2): tigervnc-server-1.1.0-24.el6.x86_64.rpm                                        | 1.0 MB       00:00
--------------------------------------------------------------------------------------------------------------
Total                                                                        670 kB/s | 1.0 MB       00:01
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
    Installing : libxshmfence-1.2-1.el6.x86_64                                                           1/2
    Installing : tigervnc-server-1.1.0-24.el6.x86_64                                                     2/2
    Verifying : libxshmfence-1.2-1.el6.x86_64                                                            1/2
    Verifying : tigervnc-server-1.1.0-24.el6.x86_64                                                      2/2

Installed:
    tigervnc-server.x86_64 0:1.1.0-24.el6

Dependency Installed:
    libxshmfence.x86_64 0:1.2-1.el6

Complete!

This Complete! message means, Installation of Tiger VNC Server was successful on your Linux machine. Once it is installed we’re good to setup VNC User.


4. Now, Edit VNC Server Configuration file and add below entries.

[[email protected] /]# vi /etc/sysconfig/vncservers
# The VNCSERVERS variable is a list of display:user pairs.
#
# Uncomment the lines below to start a VNC server on display :2
# as my 'myusername' (adjust this to your own). You will also
# need to set a VNC password; run 'man vncpasswd' to see how
# to do that.
#
# DO NOT RUN THIS SERVICE if your local area network is
# untrusted! For a secure way of using VNC, see this URL:
# https://access.redhat.com/knowledge/solutions/7027

# Use "-nolisten tcp" to prevent X connections to your VNC server via TCP.

# Use "-localhost" to prevent remote VNC clients connecting except when
# doing so through a secure tunnel. See the "-via" option in the
# `man vncviewer' manual page.

 VNCSERVERS="1:root 2:oracle"
 VNCSERVERARGS[1]="-geometry 1360x768"
 VNCSERVERARGS[2]="-geometry 1360x768"

And then save and exit.

[ESC] > :wq > Enter (to save and exit)


5. VNC Service by default runs on 5900 to 6000 port range. Now make sure your firewall allows inbound connection for VNC Service on given ports.

  • Edit iptables file located in /etc/sysconfig and add below lines (after the entry of port 22) to open 5901 and 5902 port on firewall.
[[email protected] /]# vi /etc/sysconfig/iptables 
-A INPUT -m state --state NEW -m tcp -p tcp --dport 5901 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 5902 -j ACCEPT

And then save and exit.

[ESC] > :wq > Enter (to save and exit)

Your iptables should look like,

[[email protected] /]# cat /etc/sysconfig/iptables
# Firewall configuration written by system-config-firewall
# Manual customization of this file is not recommended.
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 1521 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 5901 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 5902 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 1158 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT

6. Once we’re done with vnc and iptables configuration, then we have to set vnc password for both users, root and oracle.

  • To do this we will issue following command.

For root

[[email protected] /]# vncpasswd
Password: [enter password]
Verify: [verify password]

For oracle

[[email protected] /]# su - oracle
[[email protected] ~]$ vncpasswd
Password: [enter password]
Verify: [verify password]

7. Now, restart both the linux services vnc and iptables.

VNC

[[email protected] /]# service vncserver restart
Shutting down VNC server:                                                                 [ OK ]
Starting VNC server: 1:root xauth: creating new authority file /root/.Xauthority
xauth: (stdin):1: bad display name "dbnode1.demunix.com:1" in "add" command

New 'dbnode1.demunix.com:1 (root)' desktop is dbnode1.demunix.com:1

Creating default startup script /root/.vnc/xstartup
Starting applications specified in /root/.vnc/xstartup
Log file is /root/.vnc/dbnode1.demunix.com:1.log

2:oracle ORACLE PROFILE LOADED
xauth: creating new authority file /home/oracle/.Xauthority
xauth: (stdin):1: bad display name "dbnode1.demunix.com:2" in "add" command

New 'dbnode1.demunix.com:2 (oracle)' desktop is dbnode1.demunix.com:2

Creating default startup script /home/oracle/.vnc/xstartup
Starting applications specified in /home/oracle/.vnc/xstartup
Log file is /home/oracle/.vnc/dbnode1.demunix.com:2.log                                   [ OK ]

And iptables

[[email protected] /]# service iptables restart
iptables: Setting chains to policy ACCEPT: nat mangle filte                         [ OK ]
iptables: Flushing firewall rules:                                                  [ OK ]
iptables: Unloading modules:                                                        [ OK ]
iptables: Applying firewall rules:                                                  [ OK ]

Cheers !! We’re done setting up everything now. Let’s try to connect via VNC client now.

This is the screenshot from VNC Viewer client for Google Chrome.

Let’s enter in hostname:display number format. Here dbnode1.demunix.com is hostname and we’re trying to connect to display 1 which is configured for root user in /etc/sysconfig/vncserver file.


You maybe prompted with Unencrypted Connection warning. check the checkbox saying Do not warn me for hostname again to avoid future warnings and click on connect.

VNC Setup


Enter VNC password set for root user.

VNC Setup


And here is the Remote Display access of the server on TigerVNC Server.

VNC Setup


Here we go, we’ve successfully configured TigerVNC Server on Oracle Enterprise Linux 6.7.

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Peace 🙂

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