From: Eric Dumazet <eric.dumazet@gmail.com>
To: Olaf van der Spek <olafvdspek@gmail.com>
Cc: netdev@vger.kernel.org
Subject: Re: Enable syn cookies by default
Date: Wed, 21 Oct 2009 09:25:06 +0200 [thread overview]
Message-ID: <4ADEB752.50103@gmail.com> (raw)
In-Reply-To: <b2cc26e40910210017v3885b18dre5021c8a920f30d7@mail.gmail.com>
Olaf van der Spek a écrit :
> On Thu, Oct 15, 2009 at 10:59 AM, Olaf van der Spek
> <olafvdspek@gmail.com> 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?
>>>
>>> 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?
>
> Anybody?
This is a user selectable setting. What's wrong with /etc/sysctl.conf ?
next prev parent reply other threads:[~2009-10-21 7:25 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
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 [this message]
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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