Remote Console

Grant Peel gpeel at
Sun Oct 16 06:19:03 PDT 2005

Hi all,

RS-232 Serial Port hubs seem to be a little hard to come by, and the ones I 
have found are quite expensive.

COuld we could achieve the same using USB terminals and a 16 port USB hub?


----- Original Message ----- 
From: "Andrew P." <infofarmer at>
To: "Grant Peel" <gpeel at>
Cc: <freebsd-questions at>
Sent: Sunday, October 16, 2005 8:44 AM
Subject: Re: Remote Console

On 10/16/05, Grant Peel <gpeel at> wrote:
> Thanks Andrew,
> So If I understand your reply, a setup like this should always give me
> access to any of the servers by SSHing to one server, then CUing to get to
> the console of the 'broken' one, regardless of its state (assuming the 
> disks
> are OK, and boot stage 1 worked):
> (WAN Shown, LAN Same, using seperate nics on Servers and Switch)
>                                   ISP's router
>                                         |
>                                     My Switch
> --------------------------------------------------------------------------------
> |                  |                    |                   |
> |
> Serv1            Serv2                Serv3               Serv4
> Serv5
> Serial1--------->Serial2
>                  Serial1------------->Serial2
>                                       Serial1------------>Serial2
> Serial1---------->Serial2
> Can more than 1 console access type be specified in loader.conf ?
>     i.e.
>         console='serialconsole'
>         console='videoconsole'
> When using 'serial console, does anything have to be specified to use 
> serial
> 2?
> What is the default local console, how is it specified?
>     i.e. the one you use when you plug a keyboard and monitor directly 
> into
> the machine?
> Would I need to install any other software other than the client (CU)?
> -GRant

I haven't configured comconsoles myself, I just happen
to work at a place where they are used heavily (Sun
ALOM mostly, but built-in LOMs and FreeBSD software
comsonsoles also). Please consult the Handbook and
google, I'm sure there's nothing difficult to it.

I would not support your chaining idea, though. It's
the only one that requires $0.00 budget, but COM
hubs are cheap today. If you rent rackspace, I'm
sure your colocation provider can offer you some
kind of non-expensive remote management. If
rackspace is free, consider buying some hardware
(like a COM hub).

The matter is, that you'll want 9600 bps speeds
for max compatibility. While it is usable for
occasional failure recovery, chaining it would
make it lag too much.

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