From owner-freebsd-net Wed Apr 10 23:19: 8 2002 Delivered-To: freebsd-net@freebsd.org Received: from rwcrmhc53.attbi.com (rwcrmhc53.attbi.com [204.127.198.39]) by hub.freebsd.org (Postfix) with ESMTP id CEFA037B41C for ; Wed, 10 Apr 2002 23:18:55 -0700 (PDT) Received: from blossom.cjclark.org ([12.234.91.48]) by rwcrmhc53.attbi.com (InterMail vM.4.01.03.27 201-229-121-127-20010626) with ESMTP id <20020411061855.RWKY21252.rwcrmhc53.attbi.com@blossom.cjclark.org>; Thu, 11 Apr 2002 06:18:55 +0000 Received: (from cjc@localhost) by blossom.cjclark.org (8.11.6/8.11.6) id g3B6IpR37534; Wed, 10 Apr 2002 23:18:51 -0700 (PDT) (envelope-from cjc) Date: Wed, 10 Apr 2002 23:18:51 -0700 From: "Crist J. Clark" To: Paulius Bulotas Cc: freebsd-net@FreeBSD.ORG Subject: Re: strange network conversation Message-ID: <20020410231851.B37066@blossom.cjclark.org> References: <20020410090644.GB8914@kaktusas.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20020410090644.GB8914@kaktusas.org>; from paulius@kaktusas.org on Wed, Apr 10, 2002 at 11:06:44AM +0200 X-URL: http://people.freebsd.org/~cjc/ 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 Wed, Apr 10, 2002 at 11:06:44AM +0200, Paulius Bulotas wrote: > Hello list, > > I'm seeing strange? networking behaviour with my FreeBSD server, and it > seems that this list is tne right to ask ;) > Suppose, there is outgoing connection for whom dynamic rule is created > (that's how I noticed it - ipfw logs denied packets). My 4.4-Release > FreeBSD is hostA, something on the next end is hostB - smtp server. > That's how the end of smtp session looks: > > _Host tcpflags seq nseq ack data_ > hostA ( [PSH,ACK], seq1, nseq1, ack1, "QUIT" ) > hostA ( [FIN,ACK], nseq1, -- , ack1 ) > hostB ( [[ACK], ack1, -- , nseq1) > hostB ( [PSH,ACK], ack1, nseq2, nseq1, "221 Bye") > hostA ( [RST], nseq1, -- , -- ) > hostB ( [FIN,ACK], nseq2, -- , nseq1) > hostB ( [ACK], nseq2+1, -- , nseq1+1) > hostB ( [FIN,PSH,ACK], ack1, nseq2, nseq1+1) > ... > > I'm wondering, why FreeBSD sends RST so early and hostB tries to send > something back (and that didn't match dynamic rule, which is destroyed > upon RST (I suspect))? Is that _really_ what happens because, > hostA ( [PSH,ACK], seq1, nseq1, ack1, "QUIT" ) > hostA ( [FIN,ACK], nseq1, -- , ack1 ) > hostB ( [[ACK], ack1, -- , nseq1) ^^^^^ Should be, nseq1 + 1. But I think that would explain the RST. > Is it possible to change this? (so that conversation between hostA and > hostB ended normally) If hostB's stack is really broken, not sure what to do to fix it. -- Crist J. Clark | cjclark@alum.mit.edu | cjclark@jhu.edu http://people.freebsd.org/~cjc/ | cjc@freebsd.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message