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Old 05-19-2006, 03:25 PM   #1
ivj
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Do we really need CNAME records in DNS?


I just read this article: http://support.algx.net/cst/dns/dns2.html

Basically it says that if I want to have 2 domain names pointing to 1 IP, I should do this:

A Record: onedomain.com -> IP
CNAME Record: twodomain.com -> onedomain.com

Instead of this:

A Record: onedomain.com -> IP
A Record: twodomain.com -> IP

... Is this true?

I've always used the 2nd way (2 A records), and it always worked, and besides, if you're going thru the CNAME, doesn't the user have to make 2 DNS calls instead of one?

Can someone clear up please?

Also, do we need CNAME records for anything other than this?

I guess something like

mom.domain.com -> dad.domain.com can't be accomplished via an A record, can it?
 
Old 05-19-2006, 03:33 PM   #2
acid_kewpie
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you should authoratively state that one domain is the main domain, and other domains then get cname'd to it. I would *assume* that if you ping an address only defined as a cname then the dns server follows through the relations and still only returns the end address, as that is all that you asked for, it's not like an http redirect or such.
 
Old 05-19-2006, 03:45 PM   #3
ivj
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And if I don't state that one domain is main domain? Then what? FBI is gonna be at my door?

Is there a REAL reason for CNAME being a "better" alternative to A? I can see how it's useful in some cases, but most of the time I don't really care.
 
Old 05-19-2006, 03:49 PM   #4
acid_kewpie
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no that's your call. there is no checking on it, but then if you want to do a reverse lookup on the IP there should (afaik) only be a single possible result. with multiple A's this is not guarenteed.
 
  


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