CNAME record and a MX record in 8.2.3?

[Erik Aronesty]

This whole issue is whacked.  

CNAME's should not conflict with SOA RR's.  There's absolutely nothing *explicit* in the RFC that says they must "conflict with SOA records" or get rejected.

BIND 8.2.3 implements this - but it's easy to comment out the ++errs code in load_db.c in the right places.  All browsers and resolver libraries already support CNAME's at the zone-top.

			- Erik

-----Original Message-----
From:	Mark.Andrews at nominum.com [SMTP:Mark.Andrews at nominum.com]
Sent:	Sunday, February 11, 2001 9:37 PM
To:	Tien Nguyen
Cc:	comp-protocols-dns-bind at moderators.isc.org
Subject:	Re: CNAME record and a MX record in 8.2.3?


> I was fighting the same problem and I finally using the A record and it
> works fine for us now. The funny thing is this method works fine under 8.2.2
> and we only get this problem after update to 8.2.3 for security reasons.

	It didn't work under 8.2.2.  You just ignored the error messages.

> 
> Is there any RFC explaining about these CNAME rules?

	Yes.  RFC 1034 Section 3.6.2. Aliases and canonical names.

> 
> The useful thing about using a CNAME to point MY-DOMAIN.COM to
> WWW.OTHERHOST.COM is I will never have to remember to change the A record
> for MY-DOMAIN.COM if the IP of WWW.OTHERHOST.COM changed.

	There is a draft-rfc saying how to do this with SRV records.
	All it requires is for the brower and cache writers it implement
	support.

> 
> Thanks,
> Tien Nguyen,
> 
> "Bill Larson" <wllarso at swcp.com> wrote in message
> news:9613f3$hee at pub3.rc.vix.com...
> >
> > I am assuming that the zone that this file is for is "wtul.fm".  If not,
> > everything that I say is most likely wrong.
> >
> > What it sounds like you are asking is that http;//www.wtul.fm and
> > http://wtul.fm both get redirected to the machine pulse.tcs.tulane.edu.
> >
> > You CANNOT use a CNAME record to redirect traffic for "wtul.fm" to
> > "pulse.tcs.tulane.edu".  The basic rule is that the left hand side domain
> > name that is identified with a CNAME record cannot have any other DNS
> > information associated with it.  I.e., since "wtul.fm" has SOA and
> > NS records associated with it, you cannot have a CNAME record also.
> >
> > The easiest solution is to have an "A" record for "wtul.fm" which
> > has the sam IP address as "pulse.tcs.tulane.edu".  Using a CNAME
> > record for "www.wtul.fm" is completely correct.
> >
> > You have an "A" record for "wtul.fm" which identifies
> "pulse.tcs.tulane.edu"
> > on the right hand side.  This line is commented out, so I don't know
> > if this is just a comment for yourself, but I hope so.  If you
> > were to uncomment this, you should receive an error when loading.
> > An "A" record must have an IP address on the right hand side.
> >
> > Bill Larson
> >
> > > I had a configuration file for that worked under 8.2.2-P7 . But wouldn't
> > > work in 8.2.3. I am hoping someone can suggest the correct configuration
> > > under 8.2.3.
> > > A CNAME to pulse (see below) fails, as does an A reference to pulse.
> Should
> > > I use an A record to pulse's IP address?
> > >
> > > The server currently resolves http://www.wtul.fm correctly, and sends
> the
> > > mail correctly. However, it is desired that http://wtul.fm resolve also.
> > >
> > > -------file: wtul.fm----------
> > >
> > > ;Start of our authoritative zone
> > >
> > > @       IN      SOA     ns1.tcs.tulane.edu. hostmaster.tulane.edu. (
> > >                                 2001020801 ; serial number
> > >                                 86400   ; refresh once a day
> > >                                 3600    ; retry every 60 min
> > >                                 604800  ; expire after 1 week
> > >                                 86400 ) ; TTL min 1 day
> > >
> > > ;Nameservers for this zone
> > >
> > >                         IN      NS      ns1.tcs.tulane.edu.
> > >                         IN      NS      ns2.tcs.tulane.edu.
> > >
> > > ;OwnerName      TTL     Class   Type    RData
> > > @                       IN      MX      0 majestic.tcs.tulane.edu.
> > > ;                       IN      A       pulse.tcs.tulane.edu.
> > > www                     IN      CNAME   pulse.tcs.tulane.edu.
> >
> >
> 
> 
--
Mark Andrews, Nominum Inc.
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at nominum.com