CNAME vs A?

[Barry Margolin]

In article <6XEpOSyb=EsAYalwX4k8mXGYy7pE at 4ax.com>,
Dave Lers  <davelers at home.com> wrote:
>I posted a similar question w/ no reply, this is bugging me so I'm
>trying again.
>
>I know the following is correct
>
>dalrun.com.		IN	A	24.16.244.57
>www.dalrun.com.		IN	CNAME	dalrun.com.
>dalrun.com.		IN	MX      5	dalrun.com.
>dalrun.com.		IN	NS	dalrun.com.
>
>but I have seen the following also claimed to be correct, nslint tells
>me its not and, with one exception, I've never seen it used in the

What does nslint think is wrong?  Does it complain about multiple A records
pointing to the same address?  IMHO, this is nslint's author asserting a
personal opinion.  There's nothing technically wrong with multiple names
pointing to the same address.

>documentation I've found, yet I also haven't seen anything that says
>its a bad thing. An aye or nay with an explanation, or a pointer to
>one, would be appreciated.
>
>dalrun.com.		IN	A	24.16.244.57
>www.dalrun.com.		IN	CNAME	dalrun.com.
>mail.dalrun.com.		IN	A	24.16.244.57
>dalrun.com.		IN	MX      5	mail.dalrun.com.
>ns1.dalrun.com.		IN	A	24.16.244.57
>dalrun.com.		IN	NS      	ns1.dalrun.com.
>
>I've seen it 2x in a row now with NS records (different A records
>using the same IP). With CNAME's and aliases in Apache I'm fine (and
>sendmail looks doable the same way) but what about DNS ?, with a
>single IP it seems I'm stuck with dalrun.com. Am I missing something,
>is there an acceptable way, with a single IP, to use ns1.dalrun.com
>for my NS record?

MX and NS records shouldn't point to CNAME records, so you can't replace
the ns1 and mail records with CNAMEs in the second version.

-- 
Barry Margolin, barmar at genuity.net
Genuity, Burlington, MA
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