cname quick question

Tal Dayan tal at zapta.com
Tue Feb 27 19:01:39 UTC 2001



(The CNAME issue from a simple user view point)

Writing a URL in the right hand of a CNAME is definitely a mistake, BIND
does not deal with URL forwarding.

However, having a CNAME name record for the domain itself makes sense, is
useful, and will make the life easier for many BIND users like us.

With a CNAME record, we will not have to risk downtime until we update the A
record each time Yahoo (in the example mentioned earlier) change their IP.
And this is after all why the CNAME records are made for, isn't it ? So
there must be a good reason to defeat the the purpose of the CNAME for the
special case of the domain itself.

And the fact that this issue comes up every week or so as Cricket says,
indicates that the need is real and not just a theoretical issue.

Will the people that are trusted with the future of BIND its future (great
job, thanks),  please explain their motivation not to allow the use of CNAME
record for the domain itself. I wonder if there is some deep problem here
that I can't see myself.

And if the issue is just a matter of legality with current standards and is
not problematic by itself, what are the forums to direct a request to
include this feature in coming versions of the standards ?

Thanks,

Tal


> -----Original Message-----
> From: bind-users-bounce at isc.org [mailto:bind-users-bounce at isc.org]On
> Behalf Of Cricket Liu
> Sent: Saturday, February 03, 2001 4:29 PM
> To: bind-users at isc.org
> Subject: Re: cname quick question
>
>
>
> > Interesting, so that means you cannot have a CNAME at the "zone top" in
> any
> > "file", but you can achieve this same exact effect by putting
> the CNAME in
> > the file above it
> >
> > For example:
> >
> > I need to CNAME for myname.com to store.yahoo.com.
> >
> > I tested this and it works/validates - but it seems like a clumsy
> > workaround.
> >
> > I had to put the "myname.com." CNAME record in a "com.dom" file. Then I
> add
> > "com.dom" as the zone file handling "com." in the conf. I then make sure
> the
> > nameserver is not being used by any machines for recursive service so it
> > can't mislead people about the "com." zone.
> >
> > Is the only way to achieve a CNAME for myname.com to
> store.yahoo.com.?  I
> > cannot replicate the canonical record set (no permissions).
>
> No, you just plain can't have a CNAME record for myname.com.  If
> myname.com exists at all, it needs to be delegated from com by NS
> records.  (VeriSign GRS will not add a CNAME record to the com
> zone for you.)  And if the domain name myname.com owns NS records,
> it can't also own a CNAME record.
>
> This whole "CNAMEing the domain name of a zone" business comes
> up at least once a week because someone wants the domain name of
> their zone to point to the domain name of their web server.  Some folks
> even try to put URLs in the CNAME record.  The solution is to add an
> address record pointing your zone's domain name to the the address of
> your web server.
>
> cricket
>
>
>



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