DNS DoS ???
Blake T. Pfankuch
blake at pfankuch.me
Fri Jul 29 21:33:27 UTC 2011
I've seen this for the same on about 3 sets of nameservers I operate. fail2ban doing a 72 hour iptables drop rule.
-----Original Message-----
From: Drew Weaver [mailto:drew.weaver at thenap.com]
Sent: Friday, July 29, 2011 3:01 PM
To: 'Elliot Finley'; nanog at nanog.org
Subject: RE: DNS DoS ???
We've been seeing this for several years on and off.
thanks,
-Drew
-----Original Message-----
From: Elliot Finley [mailto:efinley.lists at gmail.com]
Sent: Friday, July 29, 2011 2:51 PM
To: nanog at nanog.org
Subject: DNS DoS ???
my DNS servers were getting slow so I blocked recursive queries for all but my own network.
Then I was getting so many of these:
ns2 named[5056]: client 78.159.111.190#25345: query (cache) 'isc.org/ANY/IN' denied
that is was still slowing things down. I've since written a script to watch the log and throw these into the box local firewall. If I expire the entries after 24 hours then I accumulate about 10200 unique IPs. If I expire after 48 hours, then it's just over 20000 unique IPs.
Is anyone else seeing this?
Elliot
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