You can use jabber.example.com provided you’‘ve setup your DNS records properly. You’'ll need a CNAME for jabber to point to server3. Additionally, to be complete (especially if you want to openly federate), a xmpp-server SRV record that points to the jabber server as well.
Keep in mind, while technically possible to change the hostname afterwards, it is a pain as it involves updating contact subscriptions/buddies so try to get it right the first time.
I just did set up openfire with server3 So I have to change it afterwards… Or well I guess I’'ll just make a fresh install with everything right. Can I uninstall with rpm -e or are there some more files I need to remove?
About the DNS being properly set up… Do you know where I can make these settings in cpanel/whm (just bought cpanel/whm so I’'m not quite sure where those settings are)
If you’‘re not too far along, I’‘d recommend uninstalling and reinstalling. I’‘m running the inside tomcat, so I can’'t tell if the rpm -e clears out your config file or not. I would imagine it does. Wildfire is self contained so you could always rm the directory.
You don’‘t want to set it up as a subdomain, rather you just need a CNAME to the host you’‘re on. This will suffice for wildfire on a LAN. If you plan on federating, you’'ll need the SRV records to ensure compatability. (for instance, google checks for SRV records)
Sorry, I don’‘t have use CPANEL so I can’‘t walk you through the DNS setup. What I’‘m telling you to do isn’‘t far fetched so I’‘m sure there’'s a way. If you have access to the DNS configuration files, you might edit them manually.