RE: MS explains

If Microsoft's problem was with routing to their DNS network, why did MX
records resolve just fine?
I'm afraid I don't understand that part.

Is there policy routing or load balancing or something that can route MX
requests to one set of dns servers while routing host requests to another
set of DNS servers?

As far as I can tell today, responses to my requests of the same DNS server
for host records and MX records are returning from the same IP,, so it doesn't appear to me that different DNS servers are
responding to different types of requests.

I was wondering that as well. Oh, and it seems to have happened again...
I'm getting timeouts for and as yesterday. Although
one box that has it cached has a 54 minute TTL, so I'm guessing it happened
recently. has been updated. Jan 25th
outage was a DoS attack.