MX question

[Mark_Andrews at isc.org]

> What the advantage to doing this:
> ;; ANSWER SECTION:
> microsoft.com.          6789    IN      MX      10 maila.microsoft.com.
> microsoft.com.          6789    IN      MX      10 mailb.microsoft.com.
> microsoft.com.          6789    IN      MX      10 mailc.microsoft.com.
> 
> ;; ADDITIONAL SECTION:
> maila.microsoft.com.    6789    IN      A       131.107.3.125
> maila.microsoft.com.    6789    IN      A       131.107.3.124
> mailb.microsoft.com.    6789    IN      A       131.107.3.122
> mailb.microsoft.com.    6789    IN      A       131.107.3.123
> mailc.microsoft.com.    6789    IN      A       131.107.3.121
> mailc.microsoft.com.    6789    IN      A       131.107.3.126
> 
> As opposed to just listing more MX's like:
> ;; ANSWER SECTION:
> microsoft.com.          6789    IN      MX      10 maila.microsoft.com.
> microsoft.com.          6789    IN      MX      10 mailb.microsoft.com.
> microsoft.com.          6789    IN      MX      10 mailc.microsoft.com.
> microsoft.com.          6789    IN      MX      10 maild.microsoft.com.
> microsoft.com.          6789    IN      MX      10 maile.microsoft.com.
> microsoft.com.          6789    IN      MX      10 mailf.microsoft.com.
> 
> ;; ADDITIONAL SECTION:
> maila.microsoft.com.    6789    IN      A       131.107.3.125
> mailb.microsoft.com.    6789    IN      A       131.107.3.124
> mailc.microsoft.com.    6789    IN      A       131.107.3.122
> maild.microsoft.com.    6789    IN      A       131.107.3.123
> maile.microsoft.com.    6789    IN      A       131.107.3.121
> mailf.microsoft.com.    6789    IN      A       131.107.3.126
> 
> Is the advantage round-robin?

	No.  Just information transfer efficency.  Think about the
	response to ANY queries.

	Mark
--
Mark Andrews, Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at isc.org