MX Record Configuration
Kevin Darcy
kcd at daimlerchrysler.com
Wed Nov 1 00:37:00 UTC 2006
Barry Finkel wrote:
> Kevin Darcy replied to a posting:
>
>
>> There's nothing magical about the first label of the name, in SMTP
>> terms. The only thing that really matters in terms of SMTP failover is
>> the preference value. If your box -- whatever it's called -- has a
>> preference of 5 and your ISP's box -- whatever it's called -- has a
>> preference of 10, then mail will be delivered to your box, if possible,
>> and only if it is not possible will sending MTAs fail over to your ISP's
>> server.
>>
>
> When I last looked at spam statistics on our backup mail relay box,
> I found that 25% of the mail to that box was legitimate mail, and
> 75% was spam. I know that our primary mail relay box was not
> unavailable 25% of the time, so there are mailers on the Internet
> that do not follow the rules in the MX RFC. I did not have time to
> look at some of the mail to try to determine what mail software
> delivered the mail to the higher preference MX host
>
It's true that some spammers deliberately subvert the SMTP algorithm in
an attempt to find a "soft" mail gateway that doesn't apply the same
anti-spam rigor to incoming mail.
But I'm not aware of any spammer giving any special meaning to mail
gateway names with a first label of "mail" or "post" or whatever, which
was what I was responding to above.
- Kevin
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