What are these Google IPs hammering on my DNS server?

Sun Dec 3 21:45:36 UTC 2023

On Sun, 3 Dec 2023, Michael Hare wrote:
> 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.

Assuming it's really Google and Cloudflare, it is probably not malicious, 
just very inept mail admins.

They assume that abuse.net is some sort of DNSBL so they configure their 
mail server to query it for every domain in every message they see, even 
though the results are useless.  I have never been able to get anyone who 
does this to stop.

It's not unlike the multirbl page at valli.org which proves the truism 
that any idiot can run a blacklist and many idiots do.  He included the 
abuse.net results and despite a warning right next to the results saying 
it's not a blacklist, I got a stream of outraged people insisting I was 
personally blocking their mail.  So I was finally able to get him to take 
it out by returning this custom result:

'Blacklisted.  To remove send $100 to xx at valli.org'

R's,
John
>
> 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 at nanog.org> On
>> Behalf Of John R. Levine
>> Sent: Sunday, December 3, 2023 1:18 PM
>> To: Peter Potvin <peter.potvin at accuristechnologies.ca>
>> Cc: nanog at 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.