From owner-freebsd-net@FreeBSD.ORG  Tue Dec  2 02:02:49 2014
Return-Path: <owner-freebsd-net@FreeBSD.ORG>
Delivered-To: freebsd-net@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by hub.freebsd.org (Postfix) with ESMTPS id 50D58305
 for <freebsd-net@freebsd.org>; Tue,  2 Dec 2014 02:02:49 +0000 (UTC)
Received: from shell1.rawbw.com (shell1.rawbw.com [198.144.192.42])
 by mx1.freebsd.org (Postfix) with ESMTP id 3BD0EBC3
 for <freebsd-net@freebsd.org>; Tue,  2 Dec 2014 02:02:48 +0000 (UTC)
Received: from eagle.yuri.org (c-73-162-232-245.hsd1.ca.comcast.net
 [73.162.232.245]) (authenticated bits=0)
 by shell1.rawbw.com (8.14.9/8.14.9) with ESMTP id sB222mQZ005393
 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO)
 for <freebsd-net@freebsd.org>; Mon, 1 Dec 2014 18:02:48 -0800 (PST)
 (envelope-from yuri@rawbw.com)
X-Authentication-Warning: shell1.rawbw.com: Host
 c-73-162-232-245.hsd1.ca.comcast.net [73.162.232.245] claimed to be
 eagle.yuri.org
Message-ID: <547D1DC6.8030408@rawbw.com>
Date: Mon, 01 Dec 2014 18:02:46 -0800
From: Yuri <yuri@rawbw.com>
User-Agent: Mozilla/5.0 (X11; FreeBSD amd64;
 rv:31.0) Gecko/20100101 Thunderbird/31.2.0
MIME-Version: 1.0
To: freebsd-net@freebsd.org
Subject: Re: Can multiple apps listen for TCP on the same port?
References: <547C5DD3.90604@rawbw.com>
In-Reply-To: <547C5DD3.90604@rawbw.com>
Content-Type: text/plain; charset=windows-1252; format=flowed
Content-Transfer-Encoding: 7bit
X-BeenThere: freebsd-net@freebsd.org
X-Mailman-Version: 2.1.18-1
Precedence: list
List-Id: Networking and TCP/IP with FreeBSD <freebsd-net.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-net>,
 <mailto:freebsd-net-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-net/>
List-Post: <mailto:freebsd-net@freebsd.org>
List-Help: <mailto:freebsd-net-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-net>,
 <mailto:freebsd-net-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 02 Dec 2014 02:02:49 -0000

I figured it out. This is 'nc' from the base, imported from OpenBSD 5.6.

nc has two flaws in its code: it listens with backlog=5 (not 1), and it 
doesn't close the listening socket after accept, only after client is 
done communicating.
Fixing these two problems makes my app work.

I first confused it with net/netcat from ports, which is totally 
different codebase, and isn't duplex. Looking into their code confused 
me into making original wrong assumptions.

Thanks!
Yuri