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Date:      Thu, 25 Jul 2013 14:51:19 +0200
From:      Andre Oppermann <andre@freebsd.org>
To:        lev@FreeBSD.org
Cc:        "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>
Subject:   Re: A huge amount of "sonewconn: pcb 0xfffffe0053916dc8: Listen queue overflow: 193 already in queue awaiting acceptance" in logs recently (9-STABLE)
Message-ID:  <51F11F47.2000008@freebsd.org>
In-Reply-To: <932442845.20130725144622@serebryakov.spb.ru>
References:  <932442845.20130725144622@serebryakov.spb.ru>

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On 25.07.2013 12:46, Lev Serebryakov wrote:
> Hello, Freebsd-net.
>
>   I have 9.1-STABLE r253105 system, which started to flood logs with
>   "sonewconn: pcb 0xfffffe0053916dc8: Listen queue overflow: 193 already in
> queue awaiting acceptance" messages (there are thousnds of it, if you take
> "last message was repeated 600 times" in account).
>
>   Nothing was changed in settings for long time.
>
>   How could I determine, which connections (listen port, at least) cause
> these messages?

This means the rate of incoming connection attempts is grater than the speed
of the application accepting them.  Typically you either suffer from a DoS
attack or your server is undersized for the amount of traffic it is receiving.

A change to rate-limit the number of these messages is in the works to prevent
it filling from the logs too fast.

-- 
Andre




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