[Outages-discussion] Mixed Case of.mil MX Servers?

[Tom Perrine]

Looks like they're trying to encode information to tell where the DNS
lookup came from OR which server answered, if there are multiple DNS
servers in an anycast configuration.  Useful for debugging perhaps.

AV+M for the MXs and M for the sec-jeemsg from US east coast
V+L for the MXs and L for the sec-jeemsg from US west coast
A+L for the MXs and L for the sec-jeemsg from EU

They all claim to be responses from the same DNS server
(199.252.154.234), which could either be using some kind of geo or
other lookup on the source IP of the lookup to pick the response, OR
these could be responses from 2 or more different DNS servers (in
different datacenter) if there's anycast DNS involved.

traceroutes to the DNS server IP address from the different sources
might be interesting.

Also, look at the response times - west coast is 80ms, east coast is
30 and EU is 20 ms.  That's.... interesting :-)



On Mon, Oct 27, 2014 at 6:47 PM, Jim Popovitch <jimpop at gmail.com> wrote:
> On Mon, Oct 27, 2014 at 7:58 PM, Jeremy Chadwick via Outages
> <outages at outages.org> wrote:
>> Is it possible for someone to provide output from something like
>> "dig mx navy.mil. +trace" ?
>
> Here's some relevant bits of interest from USA and EU queries in which
> I see 3 different cases for the word "navy"  (nAVy, naVy, nAvy) (also:
> .MIL and .miL).  What's up with the case sensitivity?
>
> Atlanta:
> MX 20 sec-jeemsg.eemsg.mail.MIl. from server 199.252.180.234 in 30 ms.
> MX 30 mx14.nmci.nAVy.MIl. from server 199.252.180.234 in 30 ms.
> MX 30 mx13.nmci.nAVy.MIl. from server 199.252.180.234 in 30 ms.
> MX 10 pri-jeemsg.eemsg.mail.MIl. from server 199.252.180.234 in 30 ms.
> MX 30 mx15.nmci.nAVy.MIl. from server 199.252.180.234 in 30 ms.
>
> Seattle:
> MX 10 pri-jeemsg.eemsg.mail.miL. from server 199.252.155.234 in 80 ms.
> MX 20 sec-jeemsg.eemsg.mail.miL. from server 199.252.155.234 in 80 ms.
> MX 30 mx15.nmci.naVy.miL. from server 199.252.155.234 in 80 ms.
> MX 30 mx14.nmci.naVy.miL. from server 199.252.155.234 in 80 ms.
> MX 30 mx13.nmci.naVy.miL. from server 199.252.155.234 in 80 ms.
>
> Netherlands:
> MX 30 mx13.nmci.nAvy.miL. from server 199.252.154.234 in 20 ms.
> MX 30 mx15.nmci.nAvy.miL. from server 199.252.154.234 in 20 ms.
> MX 20 sec-jeemsg.eemsg.mail.miL. from server 199.252.154.234 in 20 ms.
> MX 10 pri-jeemsg.eemsg.mail.miL. from server 199.252.154.234 in 20 ms.
> MX 30 mx14.nmci.nAvy.miL. from server 199.252.154.234 in 20 ms.
>
> -Jim P.
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