From: "Nivedita Singhvi" <nivedita@us.ibm.com>
Importance: Normal
Sensitivity: 
Subject: Re: tcp_keepalive_intvl vs tcp_keepalive_time?
To: landley@trommello.org
Cc: linux-kernel@vger.kernel.org
Message-ID: <OF46DAF8B5.5C736002-ON65256B5C.0018A2C8@boulder.ibm.com>
Date: Sun, 10 Feb 2002 10:10:15 +0530
MIME-Version: 1.0
Content-type: text/plain; charset=us-ascii
Sender: linux-kernel-owner@vger.kernel.org


> Would someone be kind enough to explain the difference between
> tcp_keepalive_intvl and tcp_keepalive_time?
> Documentation/filesystems/proc.txt says tcp_keepalive_time is the
interval
> between sending keepalive probes, but doesn't mention
tcp_keepalive_intvl...

tcp starts a keepalive timer for each connection. if the connection is idle
for tcp_keepalive_time seconds, it starts sending probes to the other end.
It sends a maximum of tcp_keepalive_probes each tcp_keepalive_intvl
seconds apart, and if the other end hasnt responded by then, it drops the
connection.

default values:

tcp_keepalive_intvl = 75 seconds
tcp_keepalive_probes = 9
tcp_keepalive_time = 7200 seconds (2 hours)

> The problem I'm trying to track down is ssh connections where the
connection
> times out but the session doesn't go away until a key is pressed.  (I.E.
> blocking reads don't notice the connection going down underneath them,
not
> even if left overnight.)

not clear from the info here whats happening in your case...
(stats?)

> Rob

thanks,
Nivedita


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