Am 15.12.21 um 14:33 schrieb Andrew P.:
So why isn't there a way to tell BIND not to respond to queries for which it
clearly is not authoritative (such as these attack vectors)? Since no
legitimate resolver would be asking a non-authoritative server for information,
why should his (or my) public BIND server respond to these even with an error
message?
because in case of UDP it would make things much worser
how do the client smell that you didn't respond by purpose and distinct
it from packet loss leading to retries?
------------------
"Since no legitimate resolver would be asking a non authoritative server
for information" isn't true at all
years ago we moved a server to a different location and all sorts of ISP
resolvers did respond with old IPs months later, the dumbest one even
played lottery responding 50% old and 50% new IP
i found that out by random complaints because one domain had 60 count
subdomains and started to query all open rsolvers i was able to find
with script's - a tragedy
that machine was sadly the primary NS for 800 domains and over the
months the old ip could have been ru-used for a new customer running a
nameserver for completly different domains
------------------
long story short: no sane service should supress replies completly
unless a explicit blacklist saying so is involved
________________________________________
From: bind-users <bind-users-boun...@lists.isc.org> on behalf of Ondřej Surý
<ond...@isc.org>
Sent: Wednesday, December 15, 2021 7:18 AM
To: Danilo Godec
Cc: bind-users@lists.isc.org
Subject: Re: Millions of './ANY/IN' queries denied
Would I be doing a bad thing by using fail2ban to block these IPs?
That’s the question that only you can answer. The IP addresses are
not attacker’s but victim’s and you would be punishing those networks
by blocking access from them to your network.
Do you absolutely know that these IP addresses doesn’t need access
to your DNS? If yes, then go ahead.
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