Configuring the hostname on Red Hat Enterprise Linux

Question

On RHEL and similar distributions such as CentOS and OEL you can set the hostname by adding a hostname entry in /etc/sysconfig/network.

HOSTNAME=hydrogen.lan

If you don't have such an entry, the system will fall back to the default behaviour - referencing the hostname configured on the first matching entry in /etc/hosts.

192.168.92.101 hydrogen.lan hydrogen

Now, my question is. Are there any good reasons to use the direct hostname configuration in /etc/sysconfig/network or is it simply redundant in most scenarios?

Answer 1

The box in your example will have hydrogen.lan as its hostname, not hydrogen.

The only way I know of to have hostname return the short hostname and to have hostname -f return the FQDN, is to use both the mentioned options.

So add HOSTNAME=mybox to /etc/sysconfig/network and add

10.10.10.10 mybox.example.com mybox

to /etc/hosts. I like having hostname and hostname -f return different things. By default, Anaconda sets it up like you have it set up now.

Answer 2

It will stop the hostname mysteriously changing when someone adds another entry (for a new web site, perhaps) to /etc/hosts (or eighteen months later when the machine is rebooted).

If the hostname is changed accidentally (by someone typing hostname then fat-fingering the return key) you can see what to change it back to.

Answer 3

Running "hostname myhost" from the command line immediately changes the hostname.

I define the short or full hostname by editing /etc/sysconfig/network in order to make the name persistent across reboots.

Adding an entry in /etc/hosts with the system's IP address and FQDN and short name makes the hostname consistent for services that rely on it (apache, lpd, sendmail, etc.)

Answer 4

the hostname command always worked for me just type man hostname