Intermittent Issues Resolving Microsoft Hostnames

[John Miller]

Ok--I see what's up now!  This has been one of the stranger DNS setups
I've ever seen: different NS records pointing to overlapping sets of
IP addresses, EDNS disabled, really short TTLs on both NS and A
records.  Even though you're not querying at the name listed in the NS
records, it's usually the same IP under the hood, so

# dig +noedns zulily-com.mail.protection.outlook.com.
@ns1-prodeodns.glbdns.o365filtering.com.

should work--it's only when the nameserver itself fails to resolve
that things go funny.

If things are working for you now, I'll leave you be.  Thanks for a
really interesting problem!

John

On Wed, May 4, 2016 at 4:52 PM, Rob Heilman <rheilman at echolabs.net> wrote:
> That is a valid NS for the *.mail.oe.outlook.com hostnames.  Probably got
> wires crossed between the different examples.  Either way I could not
> resolve that server name at that time.  Now it is responding 100% of the
> time for both *.mail.oe.outlook.com and *.mail.protection.outlook.com hosts.
>
> -Rob Heilman
>
>
>
> ;mail.eo.outlook.com. IN NS
>
> ;; ANSWER SECTION:
> mail.eo.outlook.com. 10 IN NS ns2-prodeodns.glbdns.o365filtering.com.
> mail.eo.outlook.com. 10 IN NS ns1-prodeodns.glbdns.o365filtering.com.
>
> ;; ADDITIONAL SECTION:
> ns1-prodeodns.glbdns.o365filtering.com. 6 IN A 207.46.100.42
> ns1-prodeodns.glbdns.o365filtering.com. 6 IN A 65.55.169.42
> ns1-prodeodns.glbdns.o365filtering.com. 6 IN A 157.56.112.42
> ns2-prodeodns.glbdns.o365filtering.com. 30 IN A 207.46.163.143
> ns2-prodeodns.glbdns.o365filtering.com. 30 IN A 207.46.163.176
> ns2-prodeodns.glbdns.o365filtering.com. 30 IN A 157.55.234.42
>
> ;; Query time: 9 msec
> ;; SERVER: 10.10.10.21#53(10.10.10.21)
> ;; WHEN: Wed May  4 16:47:26 2016
> ;; MSG SIZE  rcvd: 210
>
>