nanog mailing list archives

RE: What are these Google IPs hammering on my DNS server?


From: Michael Hare via NANOG <nanog () nanog org>
Date: Sun, 3 Dec 2023 21:21:28 +0000

John-

This is little consolation, but at AS3128, I see the same thing to our downstream at times, claiming to come from both 
13335 and 15169 often simultaneously at the tune of 25Kpps , "assuming it's not spoofed", which is pragmatically 
impossible to prove for me given our indirect relationships with these companies.  When I see these events, I typically 
also see a wide variety of country codes participating simultaneously.  Again, assuming it's not spoofed.  To me it 
just looks like effective harassment with 13335/15169 helping out.  I pine for the internet of the 1990s.

Recent events in GMT for us were the following, curious if you see the same
~ Nov 26 05:40
~ Nov 30 00:40
~ Nov 30 05:55

Application agnostic, on the low $ end for "fixes", if it's either do something or face an outage, I've found some 
utility in short term automated DSCP coloring on ingress paired with light touch policing as close to the end host as 
possible, which at least keeps things mostly working during times of conformance.  Cheap/fast and working ... most of 
the time.  Definitely not great or complete at all, and a role I'd rather not play as an educational ISP/enterprise.

So what are most folks doing to survive crap like this?  Nothing/waiting it out?  Oursourcing DNS?  Scrubbing 
appliance?  Poormans stuff like I mention above?

-Michael 

-----Original Message-----
From: NANOG <nanog-bounces+michael.hare=wisc.edu () nanog org> On
Behalf Of John R. Levine
Sent: Sunday, December 3, 2023 1:18 PM
To: Peter Potvin <peter.potvin () accuristechnologies ca>
Cc: nanog () nanog org
Subject: Re: What are these Google IPs hammering on my DNS server?

Did a bit of digging on Google's developer site and came across this:
https://developers.google.com/speed/public-
dns/faq#locations_of_ip_address_ranges_google_public_dns_uses_to_send_
queries

Looks like the IPs you mentioned belong to Google's public DNS resolver
based on that list on their site. They could also be spoofed though from a
DNS AMP attack, so keep that in mind.

Per my recent message, the replies are tiny so if it's an amplification
attack, it's a very incompetent one.  The queries are case randomized so I
guess it's really Google.  Sigh.

If anyone is wondering, I have a passive aggressive countermeasure against
some overqueriers that returns ten NS referral names, and then 25 random
IP addresses for each of those names, but I don't do that to Google.

R's,
John

------------------------------------------------------------------------------
*Accuris Technologies Ltd.*


On Sun, Dec 3, 2023 at 1:51 PM John Levine <johnl () iecc com> wrote:

At contacts.abuse.net, I have a little stunt DNS server that provides
domain contact info, e.g.:

$ host -t txt comcast.net.contacts.abuse.net
comcast.net.contacts.abuse.net descriptive text "abuse () comcast net"

$ host -t hinfo comcast.net.contacts.abuse.net
comcast.net.contacts.abuse.net host information "lookup" "comcast.net"

Every once in a while someone decides to look up every domain in the
world and DoS'es it until I update my packet filters. This week it's
been this set of IPs that belong to Google. I don't think they're
8.8.8.8. Any idea what they are? Random Google Cloud customers? A
secret DNS mapping project?

 172.253.1.133
 172.253.206.36
 172.253.1.130
 172.253.206.37
 172.253.13.196
 172.253.255.36
 172.253.13.197
 172.253.1.131
 172.253.255.35
 172.253.255.37
 172.253.1.132
 172.253.13.193
 172.253.1.129
 172.253.255.33
 172.253.206.35
 172.253.255.34
 172.253.206.33
 172.253.206.34
 172.253.13.194
 172.253.13.195
 172.71.125.63
 172.71.117.60
 172.71.133.51

R's,
John



Regards,
John Levine, johnl () taugh com, Primary Perpetrator of "The Internet for
Dummies",
Please consider the environment before reading this e-mail. https://jl.ly

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