LinuxSA Mailing list archives

  From: John Edwards <isplist@adam.com.au>
  To  : Corey Gilmore <cfg@dln.uvm.edu>
  Date: Fri, 27 Jul 2001 09:28:11 +0930

Re: BIND question

Corey Gilmore wrote:

> Since we are paying for IP's, I am trying to use as many CNAME's as
> possible, and save the ip's for sites requiring server certificates.

There's nothing wrong with having more than 1 A record per IP, in that
way you can use A records as aliases. CNAME's are a nice idea, but by
using them you're making a resolver make 2 lookups against your DNS.
This adds latency to the request and might make a web site take that
little bit longer to load from your servers.

The main place where CNAMES are useful is for aliasing hosts for which
the addressing is not part of your realm of control. ie: if you wanted
to alias news.yourcompany.com to news.isp.com, you might not have any
guarantee that the IP address for news.isp.com will stay the same.

This is especially true for sites that use round-robin DNS and might
change at any moment with servers being added or removed from the group.

John Edwards

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