Your system hostname should be in the format host.domain.com, not domain.com.
When you run the command hostname
you should get the FQDN as host.domain.com
. The command hostname -s
gives you just the host part.
Your mail server name, website name, dns server name and the like, should always be FQDN. That said, using http://domain.com/ is non-standard. Some folks use domain.com
as their MX, they are completely clueless. That'd interpret as domain
being the host and com
being the domain name, apparently they can't be the MX for the roots.
| must a hostname for a machine also appear as an alias (CNAME) in the DNS? |
CNAME is being used by DNS illiterate admins who are completely clueless and lazy.
Say you run a mail server and apache on the same box, this box should have its system hostname set to mail.domain.com
. This mail.domain.com should also have an A record in its domain.com's zone.
If this box runs www and DNS, you need to give DNS higher priority in its hostname and preferably set its hostname as ns1.domain.com
Why so? Because ns1.domain.com is glued at roots even the dns is being down, ns1.domain.com is resolvable to an IP, which enhance reliability.
That said, your theimageengine.com
as the MX is non-standard
and decreases reliability.