From owner-freebsd-stable@FreeBSD.ORG Tue Jan 12 16:08:19 2010 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 1957F106566C for ; Tue, 12 Jan 2010 16:08:19 +0000 (UTC) (envelope-from jdc@koitsu.dyndns.org) Received: from qmta11.emeryville.ca.mail.comcast.net (qmta11.emeryville.ca.mail.comcast.net [76.96.27.211]) by mx1.freebsd.org (Postfix) with ESMTP id 6CA238FC16 for ; Tue, 12 Jan 2010 16:08:18 +0000 (UTC) Received: from omta10.emeryville.ca.mail.comcast.net ([76.96.30.28]) by qmta11.emeryville.ca.mail.comcast.net with comcast id Ue7N1d0070cQ2SLABg80mg; Tue, 12 Jan 2010 16:08:00 +0000 Received: from koitsu.dyndns.org ([98.248.46.159]) by omta10.emeryville.ca.mail.comcast.net with comcast id Ug8H1d00N3S48mS8Wg8Jp5; Tue, 12 Jan 2010 16:08:18 +0000 Received: by icarus.home.lan (Postfix, from userid 1000) id 6CD861E301C; Tue, 12 Jan 2010 08:08:16 -0800 (PST) Date: Tue, 12 Jan 2010 08:08:16 -0800 From: Jeremy Chadwick To: freebsd-stable@freebsd.org Message-ID: <20100112160816.GA99549@icarus.home.lan> References: <717f7a3e1001120714m37aada69gfaa35f0f9b17f435@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <717f7a3e1001120714m37aada69gfaa35f0f9b17f435@mail.gmail.com> User-Agent: Mutt/1.5.20 (2009-06-14) Subject: Re: Multiple serial consoles via null modem cable X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 12 Jan 2010 16:08:19 -0000 On Tue, Jan 12, 2010 at 05:14:44PM +0200, Marin Atanasov wrote: > Hello there, > > I'd like to ask you about the following - is it possible to have multiple > serial consoles coming from a single host? > > What I am talking about is connecting multiple machines using a null modem > cable - I know it is possible only to connect two machines and they need to > be connected on sio0 (COM1). > > I'm thinking about the following situation - 1 system acting like a host > with a serial port hub, each port of the hub is connected to a different > machine on sio0, using null modem cables. > > This would make the first machine something like a cheaper kind of a > terminal concentrator :) > > What do you think, have someone tried this and is it possible at all? What you're describing is basically the concept of a serial console server, where a FreeBSD box contains a multi-port serial card that's connected to multiple other servers. An individual would get on the FreeBSD box with a multiport serial card (see below) and attach to the serial port associated (wired to) whatever other box they want to log on to. Yes this is possible with FreeBSD -- but you'll need to purchase a multiport serial card that's supported natively by FreeBSD. The two I'm familiar with are Cyclades and DigiBoard, but this would've been back in the day of FreeBSD 2.2.x and I've no idea what people use present-day. I'm certain others here can recommend stuff that works. But my personal/professional opinion is that you consider purchasing an actual serial console server rather than "hack up" a FreeBSD box. Most serial console servers these days (and even old Portmasters) can do serial-to-TCP association, which allows you to literally do "telnet consoleserver NNNN" where NNNN is a TCP port which is bound to a serial port connected to each individual server. E.g. port 2000 = box#1, port 2100 = box#2, etc.. As far as present-day devices go, the ones I can recommend are the LX-series devices[1] from MRV Communications. They're Linux-based, and although may seem expensive (16-port w/out modem = ~US$1400), are a one-time purchase. Cyclades also makes identical devices, but they cost something like US$3000-4000, and they wouldn't provide me with a test/demo unit so I blew 'em off. You can also consider looking for used hardware -- either Xyplex devices (MRV bought Xyplex), or Portmaster[2] products. I believe Cisco made some devices as well. WRT Portmasters, be aware that some of the firmware images are spotty in quality (HELP commands missing, undocumented commands, etc.). There's two ports which can make interfacing/using these devices, or a multiport serial card, much easier -- Conserver[3]. I work with the guy who wrote it, so I'm biased. :-) ports/comms/conserver ports/comms/conserver-com I'm not sure what the first port is to be honest, but the 2nd port is what I'm used to using with an MRV LX-4016S device. If you'd like a bit more detail about "how it all works" (the software, the hardware, configuration details, wiring, etc.), I can describe it in greater detail. Just ask. [1]: http://www.mrv.com/oobn/ [2]: http://portmasters.com/ [3]: http://www.conserver.com/ -- | Jeremy Chadwick jdc@parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |