From owner-freebsd-questions  Thu Sep 17 10:02:52 1998
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Date: Thu, 17 Sep 1998 12:01:09 -0500
From: Dan Nelson <dnelson@emsphone.com>
To: dg@root.com, Kevin Kyeong-il CHOI <kevin.choi@cnes.fr>
Cc: FreeBSD Question <freebsd-questions@FreeBSD.ORG>,
        FreeBSD Net <freebsd-net@FreeBSD.ORG>,
        tcp-over-satellite@achtung.sp.trw.com
Subject: Re: Why FreeBSD (or Solaris as well) get stuck in case of long delay ?
Message-ID: <19980917120109.A8761@emsphone.com>
References: <006801bde208$b8e51ac0$52099584@pc-kichoi.cst.cnes.fr> <199809171437.HAA06002@implode.root.com>
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In-Reply-To: <199809171437.HAA06002@implode.root.com>; from "David Greenman" on Thu Sep 17 07:37:48 GMT 1998
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In the last episode (Sep 17), David Greenman said:
>    FreeBSD is almost certainly still using a window of 16KB. There
> are problems in the code related to changing the socket buffer size
> after the system is up. You pretty much have to modify the default
> value in the kernel source files in order to use a larger window.

I've been able to reliably increase my window by
putting this in rc.local:

sysctl -w net.inet.tcp.recvspace=65536
sysctl -w net.inet.tcp.sendspace=65536
route change default -recvpipe 65536 -sendpipe 65536
route change <insert local-net address here> -recvpipe 65536 -sendpipe 65536

Kevin: you can easily check to see what window size BSD is using by
tcpdump'ing the interface during your test:

11:54:46.789259 dan.emsphone.com.4730 > wcarchive.cdrom.com.ftp: 
  S 4230863059:4230863059(0) win 65535 <mss 1460,nop,nop,sackOK,nop,wscale 1,
    nop,nop,timestamp 6882856 0,nop,nop,ccnew 234572> (DF)

shows my window size at 64K.

	-Dan Nelson
	dnelson@emsphone.com

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