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From: Doug White <dwhite@gumbysoft.com>
To: Zoltan Frombach <zoltan@frombach.com>
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cc: freebsd-stable@freebsd.org
cc: simon@FreeBSD.org
Subject: Re: sshd stops accepting connections
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On Sat, 13 Nov 2004, Zoltan Frombach wrote:

> > Today I suddenly couldn't log in via ssh to a server I upgraded to
> > FreeBSD 5.3-RELEASE 4 days ago.  When I tried connect to port 22 using
> > telnet(1) the following just happend:
> >
> > [simon at zaphod:~] telnet 192.168.3.2 22
> > Trying 192.168.3.2...
> > Connected to jet.nitro.dk.
> > Escape character is '^]'.
> > Connection closed by foreign host.
> >
> > The servar had been running FreeBSD 5.2.1 for a while without
> > problems. ...
>
> I had the exact same problem yesterday!! I installad FreeBSD 5.3-RELEASE

[...]

> Nov 11 13:45:10 www kernel: ad0: WARNING - WRITE_DMA interrupt was seen but
> timeout fired LBA=2928095
> Nov 11 13:49:52 www kernel: maxproc limit exceeded by uid 0, please see
> tuning(7) and login.conf(5).

This is the kicker -- sshd couldn't fork because somethnig went berzerk.

> Nov 11 13:49:54 www kernel: Limiting closed port RST response from 212 to
> 200 packets/sec

This looks a lot like a SYN flood on some daemon that fork()s each
connection but doesn't have any limits.

The disk error could certainly be related, although I'm not sure
why it would cause something to spike up and hit maxproc.

-- 
Doug White                    |  FreeBSD: The Power to Serve
dwhite@gumbysoft.com          |  www.FreeBSD.org