How to Change Hostname in CentOS/RHEL/OEL

Step1) Open the file /etc/sysconfig/network in vi editor and modify HOSTNAME to FQDN (test1.abs.com)

[root@jagan1 oracle]# cat /etc/sysconfig/network

NETWORKING=yes

HOSTNAME=test1.abs.com

[root@jagan1 oracle]#

Step2) Change the hostname in /etc/hosts file 

 

Example:

192.168.72.128 test1.abs.com test1

[root@jagan1 oracle]# cat /etc/hosts

127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4

::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

192.168.72.128 test1.abs.com test1

[root@jagan1 oracle]#

step3) Run Hostname

[root@jagan1 oracle]# hostname test1.abs.com

step4) Restart networking 

 

[root@jagan1 oracle]# /etc/init.d/network restart

Shutting down loopback interface:                          [  OK  ]

Bringing up loopback interface:                            [  OK  ]

Bringing up interface eth0:  Active connection state: activating

Active connection path: /org/freedesktop/NetworkManager/ActiveConnection/2

state: activated

Connection activated                                                          [  OK  ]

[root@jagan1 oracle]#

          Restart VM 

Step5) Re-Login and verify

[root@test1 ~]# hostname -f

test1.abs.com

[root@test1 ~]#

[root@test1 ~]# dnsdomainname

abs.com

[root@test1 ~]#

Hostname changed and domain name is matching as per /etc/resolv.conf