Monday, June 28, 2010

How to Set Hostname on CentOS (RHEL)

Setting the hostname on CentOS (RHEL).

Well, I could have sworn when I ordered this VPS that I entered the hostname I wanted in the order form. I guess I must have been hallucinating....

Begin by checking the existing hostname using the hostname command.
login as: root
root@vps12's password:
Last login: Mon Jun 28 16:21:53 2010
[root@vps12 ~]# hostname
vps12
We can also check via sysctl kernel.hostname
[root@vps12 ~]# sysctl kernel.hostname
kernel.hostname = vps12
The actual hostname I need to set for this server is blanche.mydomain.net

I can set the hostname initially using the hostname command followed by the desired hostname.
[root@vps12 ~]# hostname blanche.mydomain.net
This will set the hostname:
[root@vps12 ~]# hostname
blanche.mydomain.net
However, once the server is rebooted, the hostname will revert to it's previous setting (vps12).

To permanently change the hostname, I need to edit the network file at /etc/sysconfig/network.

So,
[root@vps12 ~]# cd /etc/sysconfig
[root@vps12 sysconfig]# vi network

The Network file will look as so.

NETWORKING=yes
HOSTNAME=vps12
GATEWAYDEV=eth0
GATEWAY=192.168.0.1

Hit 'i' to insert and change the HOSTNAME value to your FQDN, in my case, blanche.mydomain.net

Hit Escape, then :wq to save and exit.

Check that the hostname is properly set:
[root@vps12 sysconfig]# hostname
blanche.mydomain.net
[root@vps12 sysconfig]# sysctl kernel.hostname
kernel.hostname = blanche.mydomain.net

Finally, if we log out, and log back in using a new session, we see I am now root@blanche:
login as: root
root@blanche's password:
Last login: Mon Jun 28 16:21:53 2010
[root@blanche ~]#  

To properly check, you may wish to reboot the server.

2 comments:

Anonymous said...

I am confused, if you directly edit the network file and reboot, do you still need to type the previous commands like "hostname example.com" ?

Anonymous said...

Thank you, this is he first page that gives user friendly info on changing hostname in centos. I'm a total newbie trying to set up my first vps, and your info helped me succeed to set the hostname.