CNAMES.. deprecated?

[Kevin Darcy]

Duncan Hill wrote:

> On 2001-03-23, Kevin Darcy did say,
>
> > The question is too simplistic. CNAMEs are not "deprecated", but
> > BIND now more rigorously enforces the "CNAME and other data" rule
> > that has existed since RFC 1034. This means that in certain
> > instances what you may have been able to (illegally) accomplish in
> > the past with CNAMEs you now have to effect with A records
> > instead. This is not "deprecation"; it's overdue enforcement.
>
> Ahh.. my only use so far has been where a machine has a DNS entry that
> matches its unix name (say einstein.pct.edu), but also needs to be
> known by other names - www and lists.
>
> The only problem that has been so far, and is proving to be again, is
> that lists under majordomo 1.94 get sent as the real host, and when
> using a linux box and pine to send mail to a cname'd host, the
> delivery is instead attempted to the real machine name.  I suppose an
> IN A and/or IN MX record might fix that.  Should dig out my bind book
> and try to work this out.

Right. CNAMEs get rewritten by MTAs. You'd need an A record or MX to
prevent that. An MX would probably be preferable, so that if you ever
readdress the server, you only have one record to change. Even if you add
the A record, it would *still* be good practice to add an MX record
pointing to it, since mail servers do MX lookups first, and so you might
conserve lookups that way.


- Kevin