An A record is an MX record and is a missing MX....

Fri Apr 4 21:24:45 UTC 2003

Of all the gin joints in all the towns in all the world, Richard Irving
had to walk into mine and say:
> 
>    Agreed, but nothing -requires- an MTA Agent have an MX record, in the first
>   place.... it is just a best CBP. Not having one means you don't comply  
>   with ALL the RFC, but you are still RFC compliant. Not the same thing, FWIW.

As part of continuing escalations in the war on spam, some MTAs are now
refusing to *accept* mail when the sender's domain does not have MX
records defined.

Whether this is a *wise* decision is becoming unimportant; people are
doing it.

-- 
Harald Koch     <chk at pobox.com>