Re: DNS Lookups

[Sarah Poger Gladstone <listmember@xxxxxxxxxxxxxx>]

Another possible setup is what AOL.com  is doing, which can be
verified by using
http://www.zmailer.org/mxverify-cgi.html and http://www.dnsstuff.com/

They have 4 MX records, each pointing to a different host name.

Then they have 3 to 4 A records for each host name, each pointing to a
different IP address.

In both cases, the order of the results changes on every request to
their DNS servers.

-Sarah Poger Gladstone


On 1/19/06, David Gibbs <david@xxxxxxxxxxxx> wrote:
> web400@xxxxxxxxxxxxxxxx wrote:
> > So the question is, how do you find out what the mail exchangers are
> > called?   The answer is: you look up the MX records.
>
> In addition, you can have more than one mail exchangers ... each with a
> priority, so that if the first mail exchanger doesn't work, the sending
> mail server will try the next, etc.
>
> I've seen domains with dozens of mail exchangers (and, in some cases,
> all of them down).
>
> Backup MX's are good if your internet connection isn't the most robust
> in the world, or if you receive a large amount of mail.  Mail servers
> have a VERY low failure tolerance, so having a backup is often a good idea.
>
> david
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