Is Hotmail in the habit of ignoring MX records?

Michael J Wise mjwise at
Sat Jul 28 02:30:40 UTC 2012

On Jul 27, 2012, at 6:40 PM, David Miller wrote:

> MX records don't "chain".

But they do, "Expand".
And I can think of a way whereby if an MX record referenced itself, *AND* included something extra … (did you see the something extra?)

That it would be possible (and I'm not saying this is what is happening, but … it could be) …
That an internal process could go resolving MX records, and adds them all to an internal table, until it figures it's got 'em all…

	"Gotta Get 'Em All!"

… and maybe, just maybe … it exhausts the table space, and gives up, and tries the A record.

I'm not saying this would be "Standard".
I'm not saying this is the best, or perhaps even an acceptable way to do it.
Or that it is in fact what is happening.

But the config looked weird, and I can imagine … a system being written as described … and breaking just this way given that MX configuration.
I can imagine Test … not catching it.

"Please have your Internet License             
 and Usenet Registration handy..."

More information about the NANOG mailing list