Date: Mon, 28 May 2007 20:29:21 +0300 From: "Abdullah Ibn Hamad Al-Marri" <almarrie@gmail.com> To: "Andre Oppermann" <andre@freebsd.org> Cc: freebsd-current@freebsd.org Subject: Re: Segment failed SYNCOOKIE? Message-ID: <499c70c0705281029o3d32c2c4k9b7467dc11e24c86@mail.gmail.com> In-Reply-To: <465AF567.6020708@freebsd.org> References: <20070525234115.GA48789@troutmask.apl.washington.edu> <499c70c0705261245k6679a12k5a0237fce786ab68@mail.gmail.com> <465AF567.6020708@freebsd.org>
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On 5/28/07, Andre Oppermann <andre@freebsd.org> wrote: > Abdullah Ibn Hamad Al-Marri wrote: > > On 5/26/07, Steve Kargl <sgk@troutmask.apl.washington.edu> wrote: > > > >> Anyone have ideas on how to cure > >> > >> May 25 16:20:03 node13 kernel: TCP: [192.168.0.15]:53815 to > >> [192.168.0.13]:50992 tcpflags 0x11<FIN,ACK>; syncache_expand: > >> Segment failed SYNCOOKIE authentication > >> > >> The hardware and kernel on 192.168.0.15 and 192.168.0.13 > >> are identical. > >> > >> -- > >> Steve > > > > 7.0-CURRENT FreeBSD 7.0-CURRENT #0: Sat May 26 04:25:29 GMT 2007 > > > > I got the same problem and my sever paniced today. > > Please provide the panic message and if available a backtrace for the > panic. We have to track down the exact cause of it (which may not > necessarily be the syncache). > > > TCP: [70.162.96.41]:54686 to [IP removed for security reasons]:59999 > > tcpflags 0x18<PUSH,ACK>; syncache_expand: Segment failed SYNCOOKIE > > authentication > > Logging of TCP segment validation failure has recently been enabled > to aid debugging of TCP (interoperability) issues. > > This particular message means that a SYN was received on a listen > socket but no matching syncache entry was found. The second test > for a syncookie also failed. Normally this means a spoofed packet > or port scan is hitting your machine. To make this certain you should > answer a couple of questions: a) What daemon is running on your port > 59999? b) Do you know [70.162.96.41] and does it have any business > in contacting your daemon on 59999? > > I agree that the log message should be made more clear to avoid > unnecessary confusion. Nothing is broken and syncache is doing its > job just fine. > > -- > Andre Hello Andre, Thanks for looking into this issue. The server IP isn't known by anyone, just me and my friend, and yes I know 70.162.96.41 which is his IP in a Linux box which runs distro Ubuntu. I run sshd in 59999, and we were both connected to it, then it died. This is a server, so I removed the debug options to not slow it down. If you think port scan could crash 7.0-CURRENT, Can you run nmap and test it 7.0-CURRENT? Do you think disabeling syncache would prevent my box against the same panic again? -- Regards, -Abdullah Ibn Hamad Al-Marri Arab Portal http://www.WeArab.Net/
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