Recently I changed the hostname of one of my machines. Ever since I did this there has been a five second pause from when I enter a command and when it actually executes. I was perplexed about this until I came across this post explaining that the /etc/hosts file was probably still pointing to the old hostname. It turns out it was!

So, to recap, if you want to change the hostname of your machine you have to make sure you do these three things:

• issue the hostname command to change the hostname while running
• update /etc/hostname with your new hostname
• update /etc/hosts to reflect your new hostname after 127.0.0.1 (get rid of the old hostname.)

Update 2/24/2015: If you happen to have a Splunk forwarder installed on the machine, make sure you update its config to reflect the new hostname. Thanks to Splunk Answers for the information.  To do this, update  $SPLUNK_HOME/etc/system/local/server.conf and change the serverName= field to your new hostname.