Bind stats - denied queries?
Reindl Harald
h.reindl at thelounge.net
Mon Nov 30 18:54:39 UTC 2020
the source of dns amplification is *always* spoofed because it's by
design the IP of the victim and not the offender
the goal of dns amplification is to flood the connection of the victim
until no regular traffic is possible
the same /24 is sharing the same line and so it doesn't make sense in
that context talk about single ip's at all
it also doesn't make sense to write abuse reports for such things
because additionally to the technical packet flood you also flood human
ressources with nosense there
they aren't the offender, they can't do anything about your issue
because the are *the victim*
you are one of thousands or even millions of hosts the attacker is
trying to get responses from to the victim
please try to understand
https://www.cloudflare.com/learning/ddos/dns-amplification-ddos-attack/
and RRL is only useful for that type of attack, everything else don't
matter for a DNS server and more important you can't distinct it anyways
Am 30.11.20 um 18:23 schrieb Marc Roos:
> Regardless if the source is spoofed or not, one should log it.
> Especially with this amazon abuse cloud, how can you report abuse, they
> want to have an ip address to be able to investigate if something
> originated from their network.
>
> If you log 0/24 you might as well log no range at all.
>
> Am 30.11.20 um 11:12 schrieb Marc Roos:
>> Are newer version of bind still logging like this
>>
>> Nov 30 10:10:02 ns0 named[1303]: rate-limit: info: limit responses to
>> 3.9.41.0/24
>> Nov 30 10:10:02 ns0 named[1303]: rate-limit: info: limit responses to
>> 35.177.154.0/24
>> Nov 30 10:10:02 ns2 named[1241]: rate-limit: info: limit responses to
>> 35.177.154.0/24
>> Nov 30 10:10:02 ns2 named[1241]: rate-limit: info: limit responses to
>> 3.9.41.0/24
>>
>> I already reported, that it is not to smart to log 3.9.41.0/24, better
>
>> could be logged 3.9.41.100/24 so you know the offending ip
>
> there is nothing like an "offending ip" in case of dns-amplification
> which is usually what happens in context of RRL
>
> it's the forged destination of the attack you see and nothing else
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