From owner-freebsd-net Tue Jul 16 21:56: 8 2002 Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 3347337B400 for ; Tue, 16 Jul 2002 21:56:06 -0700 (PDT) Received: from patrocles.silby.com (d151.as12.nwbl0.wi.voyager.net [169.207.136.153]) by mx1.FreeBSD.org (Postfix) with ESMTP id 51D5543E4A for ; Tue, 16 Jul 2002 21:56:04 -0700 (PDT) (envelope-from silby@silby.com) Received: from patrocles.silby.com (localhost [127.0.0.1]) by patrocles.silby.com (8.12.4/8.12.4) with ESMTP id g6H50Kcv079820; Wed, 17 Jul 2002 00:00:20 -0500 (CDT) (envelope-from silby@silby.com) Received: from localhost (silby@localhost) by patrocles.silby.com (8.12.5/8.12.5/Submit) with ESMTP id g6H50IgY079816; Wed, 17 Jul 2002 00:00:19 -0500 (CDT) X-Authentication-Warning: patrocles.silby.com: silby owned process doing -bs Date: Wed, 17 Jul 2002 00:00:18 -0500 (CDT) From: Mike Silbersack To: Alex Dyas Cc: net@freebsd.org Subject: Re: BSD / Firewall / 0 window size problem In-Reply-To: Message-ID: <20020716235818.K79793-100000@patrocles.silby.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org On Tue, 16 Jul 2002, Alex Dyas wrote: > I've attached a tcpdump of a Linux machine doing the same thing > (working.txt). > > the same 0 sized window can be seen: > > 17:15:56.094161 linuxbox.foo.com.3479 > solarisbox.foo.com.telnet: . ack 456 > win 5840 (DF) [tos 0x10] > 17:16:12.634540 solarisbox.foo.com.telnet > linuxbox.foo.com.3479: . ack 74 > win 0 > 17:16:12.634540 linuxbox.foo.com.3479 > solarisbox.foo.com.telnet: . ack 456 > win 5840 (DF) [tos 0x10] > > but the Linux telnet session does not freeze up as the BSD one does. > > Again, any help would be most appreciated. > > Thanks again, > > Alex... As Barney noted, the behavior of both OSes looks very similar. Have you run tcpdump on the solaris box at the same time? That win 0 packet looks _really_ suspicious to me; it doesn't share the DF bit or timestamps of the other packets in the stream. On top of that, I see no reason why a win 0 should be sent when the previous window was ~24K in size. Is it possible that the NAT box is adding it in? Mike "Silby" Silbersack To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message