MX Record Configuration

Barry Finkel b19141 at
Tue Oct 31 16:44:30 UTC 2006

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 

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.
Barry S. Finkel
Computing and Information Systems Division
Argonne National Laboratory          Phone:    +1 (630) 252-7277
9700 South Cass Avenue               Facsimile:+1 (630) 252-4601
Building 222, Room D209              Internet: BSFinkel at
Argonne, IL   60439-4828             IBMMAIL:  I1004994

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