Is Hotmail in the habit of ignoring MX records?

Ryan Rawdon ryan at
Thu Jul 26 14:10:15 UTC 2012

On Jul 26, 2012, at 2:21 AM, Suresh Ramasubramanian wrote:

> If the MX records are not responsive / timing out, they might be falling
> back to the A record.

Per RFC2821 (and later RFC5321):

   If one or more MX RRs are found for a given name, SMTP systems MUST
   NOT utilize any address RRs associated with that name unless they are
   located using the MX RRs; the "implicit MX" rule above applies only
   if there are no MX records present.  If MX records are present, but
   none of them are usable, this situation MUST be reported as an error.

So while it is possible they are doing this, they should not be

> -- 
> Suresh Ramasubramanian (ops.lists at

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