Re: Is Hotmail in the habit of ignoring MX records?

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 Ryan

-- Suresh Ramasubramanian (ops.lists@gmail.com)