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Date:      Wed, 21 May 2003 00:08:13 +0200
From:      Saulius Menkevičius <razzmatazz@mail.lt>
To:        <freebsd-stable@freebsd.org>
Subject:   Re: lots of sockets in TIME_WAIT
Message-ID:  <E19IFEH-0000Hg-64@midway.tamsa>
In-Reply-To: <20030520131538.M9634@carver.gumbysoft.com>

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Once Doug White wrote:
>On Tue, 20 May 2003, Saulius Menkevi=E8ius wrote:
>
>>I have some DDOS(?) attack on my router going where my apache=
 HTTP
>>server is flooded with short-timed connections from some host.=
 This
>>results in LOTS of sockets in TIME_WAIT/LAST_ACK/CLOSING states=
 and
>>eventually I'm out of mbufs, which, consequently means I can't=
 even
>>connect to the router from LAN. The kern.ipc.nmbclusters is=
 2560,
>>(I
>>guess high enough for router with DSL connection).
>
>TIME_WAIT is normal for a server.  LAST_ACK/CLOSING looks like 
packet
>loss.  Is your outbound link overloaded normally, or from the=
 DoS?
>
>Can you block the host? :)
>
>>    After some time all mbufs are depleted (system says "All=
 mbuf
>>cluster exhausted"). However, unexpectedly the system panics
>>shortly
>>in about 10 minutes (+/-) with:
>
>Then increase the mbufs & clusters. Did you read the tuning man=
 
page?
Ahem, I did increase mbufs, according to man page. But I wonder=
 why 
it panics. It shouldn't panic when there are no mbufs free, or=
 should 
it ?

-- 
Saulius Menkevi=E8ius, razzmatazz@mail.lt on 05.21.2003




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