Erik P. Olsen schrieb:
Thanks, so FQDN means that there MUST always be at least one dot in
the hostname. What if I use epo.dk, which is a public domain owned by
me, instead of your example olsen.intra? Does that cause any conflict?
To your first question: that a FQDN has at least one dot is a result of
its definition. Chris already gave a link. In addition
If you use a valid, because public resolvable domain name there is
always the risk that as effect a service request - here mail routing -
goes a different route than you would expect and want to. I mean, if the
resolvable domain name has DNS records poiting to different locations.
To be specific: Sendmail does MX lookups and a query for your "epo.dk"
domain gives a valid result:
$ host -t mx epo.dk
epo.dk mail is handled by 10 webhotel3.webhosting.dk.
Sure, you can try to avoid such pitfalls by doing specific setup
"tricks". But isn't it easier to simply use a namespace for your LAN
where there is no risk it would be resolvable for any public meaning?