Parent is a CNAME

[Joseph S D Yao]

On Wed, Dec 02, 2009 at 12:47:08PM +0000, Sam Wilson wrote:
> In article <mailman.1153.1259725836.14796.bind-users at lists.isc.org>,
>  Joseph S D Yao <jsdy at tux.org> wrote:
[incorrectly]
> > No.
...
> Not true.  CNAME chains - CNAMEs pointing to other CNAMEs - are 
> inefficient and discouraged but the DNS spec is built to ensure that 
> they work.  Check out www.google.com sometime (or www.google.co.uk) and 
> wonder at how many people would be annoyed if they didn't.


CNAME chains have nothing to do with this.  THIS is perfectly legal:

a	CNAME	b
b	CNAME	c
c	CNAME	d
d	CNAME	extra-ordinary

although, as mentioned, inefficient.

THIS is not legal:

a	CNAME	b
a	CNAME	c
a	A	1.1.1.1


...
> > Why not do this?
> > 
> > subdomain.b     A     7.8.9.10
> > subdomain.b     NS    ns1.subdomain.b
> > ns1.subdomain.b    A     7.9.11.13
> 
> If b was itself delegated the CNAME would be problematical again.
...


And if all the name servers crashed, then the domain would be unserved.
Why introduce unnecessary hypotheticals?  ;-)

And, as pointed out in another post, the CNAME does not appear to be
problematic in this case, even were it to exist.


-- 
/*********************************************************************\
**
** Joe Yao				jsdy at tux.org - Joseph S. D. Yao
**
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