Re: The dreadful CLOSE_WAIT

[Markus Schaber <schabios@logi-track.com>]

Hi, DervishD,

On Wed, 28 Jul 2004 16:47:23 +0200
DervishD <raul@pleyades.net> wrote:

>     Now, is there any sysctl that enables a keepalive for this kind
> of connections (dead remote end, local in CLOSE_WAIT) for all
> connections?

Hmm, on my 2.6.4 kernel, I have 

/proc/sys/net/ipv4$ for i in tcp_keepalive_* ; do echo $i $(cat $i) ; done
tcp_keepalive_intvl 75
tcp_keepalive_probes 9
tcp_keepalive_time 7200

So it seems those are only the tuning values for the keepalive. Linux
(following RFC112) by default waits for 7200 seconds = 2 hours before it
sends the probes. The reason for this is that idle connections (like
ssh) should not be dropped just because there are some temporary network
problems between the hosts. (See man tcp for details.)

It seems that there's no global enabling if you don't want to tweak the
kernel source yourself.

Markus



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