* Enable syn cookies by default
@ 2009-10-10 13:01 Olaf van der Spek
2009-10-11 10:26 ` Frans Pop
0 siblings, 1 reply; 2+ messages in thread
From: Olaf van der Spek @ 2009-10-10 13:01 UTC (permalink / raw)
To: linux-kernel
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
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: Enable syn cookies by default
2009-10-10 13:01 Enable syn cookies by default Olaf van der Spek
@ 2009-10-11 10:26 ` Frans Pop
0 siblings, 0 replies; 2+ messages in thread
From: Frans Pop @ 2009-10-11 10:26 UTC (permalink / raw)
To: Olaf van der Spek, netdev; +Cc: linux-kernel
This question is better asked on the kernel network development list.
Original mail from Olaf below.
Cheers,
FJP
=================
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
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2009-10-11 10:27 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2009-10-10 13:01 Enable syn cookies by default Olaf van der Spek
2009-10-11 10:26 ` Frans Pop
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®