Connecting to a Headless machine, after install

[Robert Watson]

On Fri, 7 May 2004, Rob wrote:

> Bruce Hunter wrote:
> > I have setup a headless machine via a null modem cable. Instalation went 
> > fine. The only problem now, is connecting to the machine after the 
> > install. When I #cu -l /dev/cuaao/
> > I see the boot process, but it gets to the date prompt but doesn't show 
> > the login:
> > i did install ssh, but won't let me login with the password I set for 
> > root. Any other methods for connecting? This system is connected in my 
> > local network, with a firewall protecting my systems.
> > - i am not running xserver on this system
...
> Funny, that I'm struggling with opposite problem: I do not get the
> boot messages over the serial cable, but do get the login prompt,
> which I do not understand :(.
> 
> For the login prompt, I have following in /etc/ttys on the headless PC:
> 
>    ttyd0   "/usr/libexec/getty std.9600"   unknown on  secure
> 
> but be sure the serial port is enabled in the BIOS, and you have
> serial port support compiled into your kernel.
> Your cu command should then work, I suppose.

You both have half of the solution, apparently, just different halves :-).
To configure my boxes for serial console operation, I do two things:

(1) Enable the ttyd0 entry in /etc/ttys by changing "off" to "on"
(2) Add the following line to /boot/loader.conf:

    console="comconsole"

    This one can be done in a couple of ways, including flags in
    boot.config for the first stage loader. 

The first action above tells init to launch getty+login on the serial
port.  The second action above tells the kernel to direct /dev/console and
low level console output to the serial port.  Note that nothing prohibits
you from leaving ttyv0 turned on when running with a serial console so you
could still log in on the VGA/keyboard console if you wanted to.  There
are also some options in conscontrol(8) to send output to multiple console
devices, but there are some limitations to multiple console operation.

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert at fledge.watson.org      Senior Research Scientist, McAfee Research