From: Jarek Poplawski <jarkao2@gmail•com>
To: Olaf van der Spek <olafvdspek@gmail•com>
Cc: netdev@vger•kernel.org
Subject: Re: Enable syn cookies by default
Date: Fri, 16 Oct 2009 08:55:41 +0000 [thread overview]
Message-ID: <20091016085541.GA7393@ff.dom.local> (raw)
In-Reply-To: <b2cc26e40910150159q68ce555fs4b1683969d939d25@mail.gmail.com>
On 15-10-2009 10:59, Olaf van der Spek wrote:
> On Sat, Oct 10, 2009 at 3:01 PM, Olaf van der Spek <olafvdspek@gmail•com> wrote:
>> Hi,
>>
>> I'm forwarding Debian feature request #520668.
>>
>> Could syn cookies be enabled by default?
Hi,
Alas, I can only give you a hint: while waiting for a better response,
you could try to 'google' for some archives of this list; AFAICR a few
(?) months ago David Miller explained this first question at least.
(In short: they aren't up-to-date enough.)
Regards,
Jarek P.
>>
>> AFAIK syn cookies only get send when the half-open TCP connection
>> queue is full. So stuff like window scaling should work fine in normal
>> situations.
>>
>> Speaking of which:
>> When the half-open TCP connection queue is full and syn cookies are
>> enabled, you get a message like "kernel: possible SYN flooding on port
>> 2710. Sending cookies."
>> However when syn cookies are disabled, you don't get any message (in
>> kern.log), although connections to your server are timing out.
>> Could such a message be added?
>> Maybe with a suggestion to increase the size of that queue or to
>> enable syn cookies.
>>
>> Greetings,
>>
>> Olaf
>>
>> http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=520668
>> http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=520667
>> https://bugs.launchpad.net/ubuntu/+bug/57091
>>
>
> Somebody?
next prev parent reply other threads:[~2009-10-16 8:55 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <b2cc26e40910100601q7aed04acjcc9973ef06e6458f@mail.gmail.com>
2009-10-11 10:26 ` Enable syn cookies by default Frans Pop
2009-10-15 8:59 ` Olaf van der Spek
2009-10-16 8:55 ` Jarek Poplawski [this message]
2009-10-16 19:01 ` Jarek Poplawski
2009-10-16 19:56 ` Florian Westphal
2009-10-16 19:49 ` [PATCH 1/2] syncookies: print synflood warning if syn queue is full Florian Westphal
2009-10-16 19:51 ` [PATCH 2/2] syncookies: enable by default Florian Westphal
2009-12-08 14:47 ` [PATCH 1/2] syncookies: print synflood warning if syn queue is full Olaf van der Spek
2009-12-08 21:09 ` David Miller
2010-01-27 17:01 ` Olaf van der Spek
2009-10-21 7:17 ` Enable syn cookies by default Olaf van der Spek
2009-10-21 7:25 ` Eric Dumazet
2009-10-21 7:48 ` Olaf van der Spek
2009-10-21 9:16 ` William Allen Simpson
2009-10-21 10:10 ` Olaf van der Spek
2009-10-21 18:36 ` William Allen Simpson
2009-10-21 18:45 ` Olaf van der Spek
2009-10-21 13:04 ` David Miller
2009-10-21 18:04 ` William Allen Simpson
2009-11-13 12:42 ` Olaf van der Spek
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