[clue-tech] linux ethernet tty-console?

[Jim Ockers]

Hi Ken,

Thanks for the reply.

Ken MacFerrin wrote:
> 
> Jim Ockers wrote:
> > Hi CLUEbies,
> > 
> > Does anyone know of a way to get the Linux kernel to provide a
> > console tty-style device over ethernet?  Sort of like telnet or 
> > ssh daemon but built into the kernel.
> > 
> > Yes I know there are security issues.  We're talking LAN only.
> > I've seen stuff like this  http://www.selenic.com/netpoll/netconsole.patch
> > which lets you see kernel printk() messages on another system via
> > ethernet using a utility like netcat or tcpdump or something.
> > 
> > We have a curses application which is the very first thing init
> > runs during boot-up.  Unfortunately if there is something wrong
> > with the system the curses application requires user interactive
> > input (type stuff in dialog boxes, move the cursor between boxes 
> > using the arrow keys, etc.).
> > 
> > Unfortunately this is on a headless server.  Yes we have a
> > serial console.  Unfortunately these systems are deployed in remote
> > locations and the serial console cable keeps getting mis-placed
> > and delivery of a new one is not possible (plus they are $70 a
> > whack, for the industrial strength explosion proof cable).
> > 
> > The ethernet cable is always connected and we're wondering if
> > there is some way to get a tty console right from the kernel via
> > ethernet so we can access the curses application over the
> > network instead of just via the serial cable which we usually
> > don't have.
> 
> I used to do something similar with my transparent pf firewall box so I
> could still access it from my LAN even though it didn't have an IP
> address.  In this case I hooked a null modem serial cable from the
> firewall box to my home server and would then ssh into my home server
> and use minicom to access the firewall console across the serial connection.
> 
> There's a good article about a similar setup using minicom and conserver
> here:
> http://www.linux.com/article.pl?sid=06/08/29/1316246

In this case our problem is caused by the lack of the null modem serial 
cable.  We always seem to have a network cable connected but no serial
console cable.

We have the agetty running on the linux box but without a null modem
serial cable connected we cannot access the console, so we are trying
to figure out if we can do something like that using just the ethernet
cable.

Thanks for the link to that article though it was good.

JimO

-- 
Jim Ockers, P.Eng. (ockers at ockers.net)
Contact info: please see http://www.ockers.net/