"LISTSERV list owners' forum" <[log in to unmask]> wrote on 
06/22/2005 01:04:57 PM:

> Because of some new anti-spam techniques being used by Earthlink, we 
have
> been instructed by Earthlink to set up an MX record for our LISTSERV
> sub-domain (lists.sierraclub.org).  For the last 10 years, we have been
> using LSMTP to route all sierraclub.org mail, including the LISTSERV 
mail.
> If setting up the new MX record does not work, I will post another 
message.

That's just stupid.  They are requiring something for outbound mail in the 
name of spam filtering??? 

Let me put on a kevlar vest to stop me from shooting you.

MX records are not normally required for the delivery of mail.  Maybe 
theirs is just of the category known as "broken."

Some spam filters check to see if there is an MX record for the domain of 
a sender, but that should never interfere with mail delivery as long as 
there is an A record for the domain in DNS.