nanog mailing list archives

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


From: Adam McKenna <adam () flounder net>
Date: Fri, 4 Apr 2003 11:40:55 -0800


On Thu, Apr 03, 2003 at 05:25:35PM -0500, Richard Irving wrote:
  It isn't exactly completely RFC compliant, but, it is only a -=Request=-, eh ?

It is in fact required that an MTA fall back to the A record for a domain if
an MX record does not exist.  See RFC 2821, Section 5, "Address Resolution 
and Mail Handling".

Obviously some admins I have encountered are starting to host mailservers
for sub-domains and domains without MX entries on their DNS zone records.
Relying on the A record alone.

   Lemmings make a mad dash towards a cliff, every so often, en masse....

This is a fallacy perpetrated by Disney.

http://www.snopes.com/disney/films/lemmings.htm

--Adam


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