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Re: FTP keep alive connection

From: Michel Loiseleur <>
Date: Thu, 8 Nov 2007 16:15:41 +0100

Le Thursday 08 November 2007 14:31:07 Robert Iakobashvili, vous avez écrit :
> Gentlemen,
> > To the contrary, the SO_KEEPALIVE approach is working well. The
> > patch is
> > nonintrusive and do not force us to add some more flags or more options
> > on compile time.
> >
> > Here is the sysctl call :
> > $ sudo sysctl -w sysctl -w net.ipv4.tcp_keepalive_time=x
> Sure, it works.
> However, there are certain doubts with regards to its non-intrusiveness.
> The default TCP KA timeout is about 2 hours. When you change it to some
> seconds,
> all TCP connections at the host will start using it
> (and generate a certain CPU engagement).
   Those strong parameters are put on the client side, which use curl. That's
why I said it's non intrusive. It seems, IMHO, that to set the SO_KEEPALIVE
by defaut, and so have a kind of "ping" every 2 hours a right approach.

   And it left the field for strange case or hard network to set it
differetently, with a system wise parameter, not a one specific to curl.

> My strong feeling is that correction of the host-wide TCP-stack parameters
> is not a business of any application or a protocol stack, unless the whole
> host
> is devoted to that application/stack; it should be done by the host admin
> explicitly.

   That's right. And that's what this patch is about. The sysctl call is done
by the host admin, not by a postinstall script. The patch only _permits_ to
give this possibility to the admin of the computer where curl is launched.


Loiseleur Michel / SLL
Groupe Linagora
27, rue de Berri / 75008 PARIS
Tel/Fax : 01 58 18 68 28 / 01 58 18 68 29
"Ce n'est pas le logiciel qui est libre, c'est vous"
Received on 2007-11-08