OT: But I found it amusing...

[Rick Chadderdon]

One of my users just sent me a message from one of her vendors.  It
basically said, "We've removed you from our weekly update list because
you blocked our mail.  Let us know when you unblock us and I'll add you
again."  My user asked me if I could find out why the mail was being
blocked, because she needed the updates.  No problem... 

It turned out to be an SPF hardfail.  Further checking led me to guess
that someone added an mail exchanger without changing the MX entry for
the domain.  Their SPF entry is "v=spf1 mx -all".  The mails that are
getting blocked are, of course, not from their MX entry's IP address. 
But they send us, "as soon as you unblock us..."  (sigh)

To be fair, the person who sent my user that message is a sales rep and
probably saw nothing more than their mail system's bounce message. 
(Which should have, however, had an explanatory link...)  Still...  I'm
sitting here shaking my head.

Rick