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

On Thu, Jul 26, 2012 at 7:45 PM, Mark Andrews <marka@isc.org> wrote:

You don't lookup MX records for MX targets. This is basic MTA processing.

If the MX lookup fails, as apposed to returns nodata, you don't lookup the A/AAAA records and synthesis a MX record. You treat it as a soft error and queue for retry later. Again this is basic MTA processing.

And yet, Hotmail apparently is doing the exact opposite of that. Which means what 'should' happen or what 'should' be done isn't as relevant as we would all it to be. Given this, considering "unusual" things like the target of an MX record having an MX record it - whilst completely irrelevant for a well-behaved mail server - might actually be relevant here... Scott.