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From: Chuck Ebbert <cebbert@redhat.com>
To: James Nichols <jamesnichols3@gmail.com>
Cc: Eric Dumazet <dada1@cosmosbay.com>,
	Jan Engelhardt <jengelh@computergmbh.de>,
	linux-kernel@vger.kernel.org
Subject: Re: After many hours all outbound connections get stuck in SYN_SENT
Date: Tue, 18 Dec 2007 15:28:36 -0500	[thread overview]
Message-ID: <47682D74.9010509@redhat.com> (raw)
In-Reply-To: <83a51e120712181145l75a19e72o3194676b05a855a6@mail.gmail.com>

On 12/18/2007 02:45 PM, James Nichols wrote:
> 
> I've run tcpdump for all IPs during this problem.  I haven't tried
> doing it for a single explicit IP address- due to the nature of the
> workload it's very difficult to know which IPs will be hit at any
> given moment.   What I did see in the full IP captures is that the
> returning ACKs don't show up in the packet capture.  Unfortunately,
> tcpdump reported that some packets were dropped during the capture.
> Is it possible that the kernel was dropping the packets before they
> could be captured by tcpdump?
> 

The only way to get a reliable trace is to run a capture from a port
mirror on the switch the server is connected to. Capturing from inside
the server at the same time and comparing the traces could be useful.

      reply	other threads:[~2007-12-18 20:29 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-12-14 20:39 After many hours all outbound connections get stuck in SYN_SENT James Nichols
2007-12-17 23:14 ` Jan Engelhardt
2007-12-18 15:34   ` James Nichols
2007-12-18 16:05     ` Jan Engelhardt
2007-12-18 16:45       ` James Nichols
2007-12-18 17:19         ` Jan Engelhardt
2007-12-18 18:09           ` James Nichols
2007-12-18 18:14             ` Jan Engelhardt
2007-12-18 18:21               ` James Nichols
2007-12-18 18:30                 ` Jan Engelhardt
2007-12-18 18:32                 ` Eric Dumazet
2007-12-18 19:44                   ` James Nichols
2007-12-18 20:37                     ` Eric Dumazet
2007-12-18 21:20                       ` Jan Engelhardt
2007-12-19 16:53                       ` James Nichols
2007-12-19 17:07                         ` Eric Dumazet
2007-12-19 17:43                           ` James Nichols
2007-12-19 17:58                             ` Jan Engelhardt
2007-12-19 18:12                               ` James Nichols
2007-12-20 14:41                               ` Glen Turner
2007-12-20 16:37                                 ` James Nichols
2007-12-20 21:05                                   ` Ilpo Järvinen
2007-12-21  6:06                                     ` Jan Engelhardt
2007-12-21  4:51                                   ` Glen Turner
2007-12-21 13:57                                     ` James Nichols
2007-12-19 18:03                             ` Eric Dumazet
2007-12-19 21:27                               ` Ilpo Järvinen
2007-12-20 16:08                               ` James Nichols
2007-12-20 20:44                                 ` Ilpo Järvinen
2007-12-20 20:49                                 ` Justin Banks
2007-12-18 19:45                   ` James Nichols
2007-12-18 20:28                     ` Chuck Ebbert [this message]

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