On Fri, 2005-11-04 at 13:32, Derek Martin wrote:
> > > But this can also be accomplished by using an A record that points to
> > > 10.0.0.1 instead of the CNAME...
> >
> > Then you have the issue of reverse lookups which have to
> > resolve to only one of the names. Nothing enforces it, but in
> > theory the name with the A record should be the same as the
> > reverse lookup and the others should be CNAME aliases.
>
> I do this all the time; it works just fine if you use A records. Most
> software that checks reverse lookups normally only checks that the
> name resolves, not that the forward and reverse lookups match.
The other problem is that in a multi-domain environment, you may
never know when or if all of the A records that refer to some
machine are updated when the server/subnet moves. If you
have one A record, managed by the person who really assigns
the address, any number of CNAMEs can refer to it from zone
files managed by other people and you always get the right
answer.
> > myname IN CNAME yourname.yourdomain.com.
> > (and by the way, the CNAMEs above are incorrect - they should use
> > the full domain name with a trailing dot as the target even when
> > in the same domain - if the bare names work it is an accident due
> > to the clients adding a default during lookup.)
>
> Er, no... that's how named zone files are interpreted. If you don't
> include a trailing dot, BIND automatically adds the zone name (as
> determined in named.conf) to the end of it. It's not an accident.
> There's nothing special about CNAME records in that regard.
Hmmm.... I'm sure I read that somewhere long ago. Maybe I
misinterpreted the point that if you do have a full domain name
you need the trailing dot to prevent adding the default. Anyway
it is never wrong to do it that way and necessary in the
case of aliasing into a different domain (which I do frequently).
--
Les Mikesell
lesmikesell@xxxxxxxxx
