Multiple CNAMEs - howto?

[Hans den Otter]

> However, if a machine changes it's IP address, I then have to remember
> to edit 2 records (and because my zones file's in alphabetical order,
> they're at opposite ends of the file.)
> The obvious solution (well obvious to a novice ;) ) would be to do:
>
> $ORIGIN mailnetwork.co.uk.
> exchange   IN   CNAME   uk1
> exchange   IN   CNAME   uk2
> exchange   IN   CNAME   uk3

Why do you not use MX record's for this ?

So:

$ORIGIN mailnetwork.co.uk.
exchange   IN   MX 10   uk1
exchange   IN   MX 10   uk2
exchange   IN   MX 10   uk3

Any decent mail tool would use the MX record instead of the A record.