"John H. Robinson, IV" <[EMAIL PROTECTED]> writes: > because with a A record one lookup -> IP address(es) > with a CNAME one lookup -> another lookup -> IP address(es) > > CNAME cause you to at least DOUBLE the DNS lookups, DOUBLING the > potential timeouts, DOUBLING dns load > > can you do it? certainly. should you be aware of the effects WHEN you do > it? yes. you may break the rules only after you understand the rules.
There is no rule that CNAME records are only for non-local pointers. Yes, a CNAME does additional lookups. DNS traffic to leaf servers is an insignificant piece of total traffic. > > DNS entries are cached and don't cause that much traffic. > > the second and subsequent times, yes. not the first time. A local CNAME doesn't do double traffic. Suppose I have a CNAME for www.bar.baz -> fletch.bar.baz. Looking up an A record in this domain will require: query for baz. query for bar.baz. query for fletch.bar.baz. Looking up the CNAME is only 33% more traffic, not "at least double": query for baz. query for bar.baz. query for www.bar.baz. query for fletch.bar.baz.
