This article provides a guide to modify server Hostname using SSH in CentOS server.

You can use the steps below to change the hostname of a running system and update the server configuration with the new hostname details.

What is a Hostname?

In computer networking, a "hostname" is a label that is assigned to a device connected to a computer network and that is used to identify the device.

How to Modify the Hostname

On any Linux system, the hostname can be checked and modified using the ‘hostname’ command.

Here are some quick uses of the hostname command:

hostname

Without any parameters, it will output the current hostname of the system.

hostname --fqd

With the --fqd argument, hostname will output the fully qualified domain name (or FQDN) of the system.

hostname NEW_NAME

When followed by normal text string (such as "NEW_NAME" above), hostname command will set the hostname of the system to NEW_NAME. This is active right away and will remain like that until the system will be rebooted (because at system boot it will set this from some particular file configurations – see bellow how to set this permanently). You will most probably need to exit the current shell in order to see the change in your shell prompt.

CentOS/RHEL

RedHat based systems use the file /etc/sysconfig/network to read the saved hostname at system boot. This is set using the init script /etc/rc.d/rc.sysinit

/etc/sysconfig/network
NETWORKING=yes
HOSTNAME="change.domainname.com"
GATEWAY="74.63.222.209"
GATEWAYDEV="eth0"
FORWARD_IPV4="yes"

So in order to preserve your change on system reboot edit this file and enter the appropriate name using the HOSTNAME variable.

Use sysctl to Change the Hostname

You can use sysctl to change the variable kernel.hostname on CentOS server.

To utilize this method, use the following procedure.

First, to check the current hostname of the server, login via SSH and run the following command:

sysctl kernel.hostname

Now, to change the hostname of the server, login via SSH and run the following command, replacing "NEW_HOSTNAME" with the new server hostname:

sysctl kernel.hostname=NEW_HOSTNAME

The hostname will now be changed to the value entered for "NEW_HOSTNAME". To verify, you can run the hostname command discussed in the beginning of the tutorial:

hostname
NEW_HOSTNAME

You now know how to modify server hostname from SSH terminal in CentOS server.