Webmin is an open-source web-based system configuration application for Linux system administrators. It manages services like User administration, Disk management, Network, Iptables ( Firewall ), Cron, Apache, DNS, File sharing, and substantially more. Webmin applications take into account the Perl module, and they communicate via browser using TCP port 10000 with the OpenSSL library.
In this article, we can see how to install Webmin on CentOS

Step 1: Webmin YUM repository

If you like to install and update Webmin using yum, create the webmin repository. We can check the repository using the following command:

# yum repolist
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* base: mirror.nbrc.ac.in
* epel: mirrors.hustunique.com
* extras: mirror.nbrc.ac.in
* rpmforge: kartolo.sby.datautama.net.id
* updates: mirror.nbrc.ac.in
repo id repo name status
Webmin Webmin Distribution Neutral 217
atrpms Fedora Core 6 - x86_64 - ATrpms 2,755
base CentOS-6 - Base 6,518
epel Extra Packages for Enterprise Linux 6 - x86_64 11,632
extras CentOS-6 - Extras 38
rpmforge RHEL 6 - RPMforge.net - dag 4,718
repolist: 25,878

Step 2: Install Dependencies

Install the dependencies using the following command:

# yum -y install perl perl-Net-SSLeay openssl perl-IO-Tty

Step 3: Install Webmin

We are ready to install it using the yum command, which will automatically install all required dependencies.

# yum -y install webmin

Step 4: Open Port

Of course, Webmin keeps running on port 10000, so we have to open the port on our firewall to get to it. The easiest way to open the port on the firewall is by using iptables rules.

CentOS/RHEL 5/6

# iptables -A INPUT -p tcp -m tcp --dport 10000 -j ACCEPT
# service iptables save
# /etc/init.d/iptables restart

CentOS/RHEL 7

# firewall-cmd --add-port=10000/tcp
# firewall-cmd --reload

Step 5: Start Webmin

Run the following commands to start the webmin service and make it start automatically

CentOS/RHEL 5/6

# chkconfig webmin on
# /etc/init.d/webmin start

CentOS/RHEL 7

# systemctl enable webmin
# systemctl start webmin

Step 6: Access Webmin

Presently, we should be ready to get to and log in to Webmin using the URL localhost or IP and enter the username as root and password (the current root password). For remote access, simply access localhost with your remote IP address.

# http://localhost:10000/
or
# http://server-IP:10000/

Change/Reset Webmin root Password

Change the webmin root account password using the following command:

# /usr/libexec/webmin/changepass.pl /etc/webmin root secretaccess