Date: Fri, 22 Jan 2010 18:10:23 +0200 From: Marin Atanasov <dnaeon@gmail.com> To: Marin Atanasov <dnaeon@gmail.com>, Jeremy Chadwick <freebsd@jdc.parodius.com>, freebsd-hardware@freebsd.org, freebsd-stable@freebsd.org, Ronald Klop <ronald-freebsd8@klop.yi.org> Subject: Re: Multiple serial consoles via null modem cable Message-ID: <717f7a3e1001220810s11b241b7ve9a9172c51ea531b@mail.gmail.com> In-Reply-To: <20100122080223.GA6681@titania.njm.me.uk> References: <717f7a3e1001120714m37aada69gfaa35f0f9b17f435@mail.gmail.com> <44678539@bb.ipt.ru> <717f7a3e1001142234y1de7ae15x6853e3ddcab4add9@mail.gmail.com> <op.u6oij7dz8527sy@212-123-145-58.ip.telfort.nl> <717f7a3e1001192246o4dce4a82q57c05ff3f41b5feb@mail.gmail.com> <20100120074611.GA405@icarus.home.lan> <717f7a3e1001210137p7884adcbxc66a4f7fff928821@mail.gmail.com> <20100122080223.GA6681@titania.njm.me.uk>
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On Fri, Jan 22, 2010 at 10:02 AM, N.J. Mann <njm@njm.me.uk> wrote: > In message <717f7a3e1001210137p7884adcbxc66a4f7fff928821@mail.gmail.com>, > Marin Atanasov (dnaeon@gmail.com) wrote: > > Hello Jeremy, > > > > Now I'm a little confused :) > > > > I've made some tests with my machines and a couple of null modem cables, > and > > here's what I've got. > > > > On Wed, Jan 20, 2010 at 9:46 AM, Jeremy Chadwick > > <freebsd@jdc.parodius.com>wrote: > > > > > On Wed, Jan 20, 2010 at 08:46:48AM +0200, Marin Atanasov wrote: > > > > Hello, > > > > > > > > Using `cu' only works with COM1 for me. > > > > > > > > Currently I have two serial ports on the system, and only the first > is > > > able > > > > to make the connection - the serial consoles are enabled in /etc/tty, > but > > > as > > > > I said only COM1 is able to make the connection. > > > > > > I'm a little confused by this statement, so I'll add some clarify: > > > > > > /etc/ttys is for configuring a machine to tie getty (think login > prompt) > > > to a device (in this case, a serial port). Meaning: the device on the > > > other end of the serial cable will start seeing "login:" and so on > > > assuming you attach to the serial port there. > > > > > > For example: > > > > > > box1 COM1/ttyu0 is wired to box2 COM3/ttyu2 using a null modem cable. > > > box1 COM2/ttyu1 is wired to box2 COM4/ttyu3 using a null modem cable. > > > > > > On box1, you'd have something like this in /etc/ttys: > > > > > > ttyu0 "/usr/libexec/getty std.9600" vt100 on secure > > > ttyu1 "/usr/libexec/getty std.9600" vt100 on secure > > > > > > > Here's what I did: > > > > box1 COM1/ttyd0 -> box2 COM1/ttyd0 -> using null modem cable > > box1 COM2/ttyd1 -> box3 COM1/ttyd0 -> using null modem cable > > > > On box1 I have this in /etc/ttys: > > > > ttyd0 "/usr/libexec/getty std.9600" vt100 on secure > > ttyd1 "/usr/libexec/getty std.9600" vt100 on secure > > > > Now if I want to connect to box1 from box2 or box3 through the serial > > connection it should work, right? > > But I only can connect to box1 from box2, because box2's COM port is > > connected to box1's COM1 port. > > > > >From box2 I can get a login prompt > > box2# cu -l /dev/cuad0 -s 9600 > > Connected > > > > login: > > ) > > (host.domain) (ttyd0) > > > > login: ~ > > [EOT] > > > > But if I try to connect to box1 from box3 - no success there. > > box3# cu -l /dev/cuad0 -s 9600 > > Connected > > ~ > > [EOT] > > You need to reduce the number of unknowns, e.g. where is the problem: > box1, box3 or in between. So, swap the cables on box1 so that you now > have box1:COM1 -> box3:COM1 and box1:COM2 -> box2:COM1. Now repeat the > tests above and post your results. > > > Cheers, > Nick. > -- > > Seems I've found the issue, that I'm having - a broken null modem cable :( The last time I was using that cable it was working fine. And now that I connected a second one to the machine, it seemed that only the one connected to COM1 was actually working, and I was left with the impression from the documentation that only COM1 is able to do a serial console connection. I'm very sorry to bother you like that. I'll continue setting up the servers once I get a new null modem cable. Thanks and regards, Marin -- Marin Atanasov Nikolov dnaeon AT gmail DOT com daemon AT unix-heaven DOT org
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