nanog mailing list archives

Re: Comcast residential DNS contact


From: Scott Helms <khelms () zcorum com>
Date: Wed, 3 Dec 2014 13:41:49 -0500

It's also entirely possible that the behavior observed will change because
of testing.  The more a test looks different from "normal" residential
traffic the more likely that it's going to be handled differently.


Scott Helms
Vice President of Technology
ZCorum
(678) 507-5000
--------------------------------
http://twitter.com/kscotthelms
--------------------------------

On Wed, Dec 3, 2014 at 1:37 PM, Christopher Morrow <morrowc.lists () gmail com>
wrote:

On Wed, Dec 3, 2014 at 12:54 PM, Grant Ridder <shortdudey123 () gmail com>
wrote:
Hi Everyone,

Thanks for the replies!  After reading them, i am doing some digging into
DNS RFC's and haven't found much with respect to ANY queries.  Not
responding with full results to protect against being used in an attack
makes sense.  However, I find it odd that only 1 of the 4 anycast
servers I
tried would institute this.

it's possible (jason hinted at this) that the servers in question are
not a homogeneous software set... and have different behaviour being
displayed because of that.

Also, just because you sent a packet to 4 different ip addresses
doesn't mean that they didn't end up on one or some of the same hosts
behind loadbalancers/ecmp/etc, right? (so it's not clear you are/can
test this properly from your vantage point)

-chris

(what's a bit concerning is my comcast link's not able to talk to
cdns02 at all... over ipv4 at least, v6 works, thankfully I suppose)



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