Subj : Re: Which Format for the hosts File is Correct? To : comp.os.linux From : jcb Date : Mon Dec 06 2004 09:52 pm In article , Sybren Stuvel wrote: >HansF enlightened us with: >> ... and I still do not see any place that states that a canonical >> host name is the same as a FQDN. (It's not even in RFC 952, from >> what I can tell.) > >My dictionary describes "canonical" as "The usual or standard state or >manner of something." I think in this case it means FQDN and >"canonical host name" can be interpreted as the same. I do not agree. It seems obvious to me that canonical host name is being contrasted with aliases. Remember, the hosts file predates the domain system. For example, the following could be (but is not, since I rely on dns) in my hosts file: 80.68.88.235 bytemark.stevens-bradfield.com www.stevens-bradfield.com Both FQDNs, but one canonical (and stored in an A record in the DNS), one an alias (and stored in a CNAME record in the DNS - and what is a CNAME record? It's a record that tells you the Canonical NAME for an alias.) On the other hand, in an internal network without DNS, you can still have both canonical names and aliases, without an FQDN in sight because the concept doesn't exist. The practical effect is that the canonical name is the hostname returned by an address -> hostname lookup via the hosts file. .