lkml.org 
[lkml]   [2013]   [Jan]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Doubts about listen backlog and tcp_max_syn_backlog
On 01/23/2013 02:47 AM, Leandro Lucarella wrote:
> Thanks for the info. I'm definitely dropping SYNs and sending cookies,
> around 50/s. Is there any way to tell how many connections are queued in
> a particular socket?

I am not familiar with one. Doesn't mean there isn't one, only that I
am not able to think of it.

> Then if syncookies are enabled, the time spent in connect() shouldn't be
> bigger than 3 seconds even if SYNs are being "dropped" by listen, right?

Do you mean if "ESTABLISHED" connections are dropped because the listen
queue is full? I don't think I would put that as "SYNs being dropped by
listen" - too easy to confuse that with an actual dropping of a SYN segment.

But yes, I would not expect a connect() call to remain incomplete for
any longer than it took to receive an SYN|ACK from the other end. That
would be 3 (,9, 21, etc...) seconds on a kernel with 3 seconds as the
initial retransmission timeout.

rick


\
 
 \ /
  Last update: 2013-01-23 21:02    [W:0.105 / U:26.264 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site