Very Computer

What whould my options be for handling a scenario described below?

I have Linux installed on a portable computer with an ethernet card.
The machine is desired to be 'docked' into several different network
subnets (with different IP addreses, of course!).  What are my options
for automatically changing the IP address when the machine is connected/booted?
Is bootp designed for a case like this?

Any info is welcome and encouraged : ).
Thanks

--
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   What whould my options be for handling a scenario described below?

   I have Linux installed on a portable computer with an ethernet
   card. The machine is desired to be 'docked' into several different
   network subnets (with different IP addreses, of course!).  What
   are my options for automatically changing the IP address when the
   machine is connected/booted?   Is bootp designed for a case like
   this?

Yes, bootp *can* be configured to do this (establish bootp servers on
each subnet, and disable bootp forwarding between subnets), but I
don't think Linux is designed to change IP addresses on the fly, nor
do I think it can be a bootp client.  Of course, you have the source
code, so you can make such changes.

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Quote:

> What whould my options be for handling a scenario described below?

> I have Linux installed on a portable computer with an ethernet card.
> The machine is desired to be 'docked' into several different network
> subnets (with different IP addreses, of course!).  What are my options
> for automatically changing the IP address when the machine is
> connected/booted?

The kernel boots up assuming that it's not connected to anything.  The
user then just types "location foo", where "foo" is where he is: e.g.
"location home", "location campus", etc.  So it's not automatic, but
it's easy enough to do.

Once I get my laptop running with its PCMCIA ethernet card, I'll hack
it to run on Linux.  Until then, you can have the SPARC version if you
want (just send email).

--
Keith Moore / U.Tenn CS Dept / 107 Ayres Hall / Knoxville TN  37996-1301

The Secretary will disavow any knowledge of my actions.

      What whould my options be for handling a scenario described below?

      I have Linux installed on a portable computer with an ethernet
      card. The machine is desired to be 'docked' into several different
      network subnets (with different IP addreses, of course!).  What
      are my options for automatically changing the IP address when the
      machine is connected/booted?   Is bootp designed for a case like
      this?

   Yes, bootp *can* be configured to do this (establish bootp servers on
   each subnet, and disable bootp forwarding between subnets), but I
   don't think Linux is designed to change IP addresses on the fly, nor
   do I think it can be a bootp client.  Of course, you have the source
   code, so you can make such changes.

I was just installing afew new hosts on the ethernet here.  Quite afew
times I had to fix network addresses and restart the networking.  So
what would be the problem with doing the same here?  You could have a
set of network configuration files for each docking station.  Then,
when you dock in a particular station, you could run a shellscript
which would

   a. softlink the configuration files for this station to the standard
      config files, and
   b. kill all the network daemons & then restart them.

I can't see why this wouldn't work, since yesterday I kept editing the
files & restarting the network daemons.  Or, is your emphasis on the
word "automatic".  If so, maybe some combination of the above with
bootp will do it for you.
--
Harvey Stein
Department of Mathematics
Hebrew University

Of course, you could always use RARP. That would work only when the
machine is booted. You would have a RARP server on each subnet with the
hardware address of your ethercard and the appropriate IP address. There
was a question here a while ago about RARP for Linux, but I don't
remember where you can snarf it from. Perhaps the person who answered
the post might be kind enough to repost the answer?

Hope this helps,
--
Mario Camou / EDS Mexico Client-Server Integration Team
From Mexico City, the smog capital of the world
------------------------------------------------------------------------------
My opinions are only mine, mine, MINE!

Alan

 > >Yes, bootp *can* be configured to do this (establish bootp servers on
 > >each subnet, and disable bootp forwarding between subnets), but I
 > >don't think Linux is designed to change IP addresses on the fly, nor
 > >do I think it can be a bootp client.  Of course, you have the source
 > >code, so you can make such changes.
 >
 > Linux can change IP address happily. Any in progress connections obviously
 > break. There is a bootp client and tools but I don't know of any ftp
 > site carrying them.

Does ANYBODY know where to get this? Please post...

I asked a couple weeks ago and got nothing back but a few messages
asking me to forward whatever I found out.

--
   - David A. Holland             | Nobody ever went broke underestimating

Quote:> I was just installing afew new hosts on the ethernet here.  Quite afew
> times I had to fix network addresses and restart the networking.  So
> what would be the problem with doing the same here?  You could have a
> set of network configuration files for each docking station.  Then,
> when you dock in a particular station, you could run a shellscript
> which would
>    a. softlink the configuration files for this station to the standard
>       config files, and
>    b. kill all the network daemons & then restart them.

Suppose you want to have /etc/HOSTNAME, /etc/rc.net1, /etc/rc.net2, and
/etc/foobar different for every configuration.  Symlink those four files
like this:

        /etc/HOSTNAME   -> config/HOSTNAME
        /etc/rc.net1    -> config/rc.net1
        /etc/rc.net2    -> config/rc.net2
        /etc/foobar     -> config/foobar

You have a different directory (campus, home, hell) for each configuration,
and these directories are in /etc.  /etc/config is a symlink to either
campus, home, or hell.  Changing the whole configuration just requires
changing the single symlink /etc/config.  Fun, huh?

I used this to manage Xaw libraries (change a symlink for Xaw or Xaw3d),
and for network configuration (distribute the symlinks the same for all
machines, just point the /etc/config to /net/config/whatever).

--
-- Arlie Davis

-- Computers are like Old Testament gods; lots of rules and no mercy.