Do you use your laptop in different network environments ?

If yes, the small package "netenv" might be useful for you. When booting your laptop it provides you with a simple interface from which you can choose the current network environment. If you are the first time in an environment, you can enter the basic data for later reuse.

Netenv sets up a file containing variable assignments which describe the current environment. This can be used by the pcmcia setup scheme (e.g. like the one that comes with Debian and perhaps others).

Have a look at netenv's chooser box:

Besides the basic functionality of configuring the network interface, the netenv data can be used for thinks like:

• Choose a proper XF86Config

  Think of using your laptop standalone with touchpad vs. connected to a CRT monitor along with an external mouse.

• Configuring your windowmanager

  You can set up your windowmanager according to the current location of your machine.

• Printing Environment

  The netenv data can easily be used to set up the printing environment.

Netenv is available as Debian package as well as tarball. It depends on dialog(1) for the menu system.

A word to all gurus: In this docu I try to explain things with Linux novices in mind, so be patient.

You may start reading about Basics, or begin with Installation. Having the Debian package you should be able to proceed to Configuration.

But if you are like me, you may want to directly jump to my Examples section. For those of you who really reach this line, here is a link to all the other stuff.

Basics

linux NETENV=off

. /tmp/netenv

Installation

All the others should untar the netenv package. It consists of the shell script called - you guessed it - netenv, example configuration files and documentation files.

You should copy the script netenv to the proper place. This can be /etc/init.d, but that depends ... Probably you may want to make a link, so that netenv is executed when your laptop comes up to run level 2. There is no need to do anything when the laptop is shut down.

Obviously netenv should be run before the network setup starts.

On a Debian system this is done by putting netenv in the directory /etc/rc.boot. You probably will find there 0setserial. You then may copy netenv to /etc/rc.boot/1netenv. To deal with the pcmcia setup scheme via network.opts as mentioned before, you may copy my network.opts to /etc/pcmcia.

Configuration

/etc/netenv/<NODE-NAME>-<VALUE-OF-VARIABLE-NETENV>

IPADDR=123.456.78.9
DOMAIN=buzz.foobar.org

Examples

netenv_id=Laptop_at_home_crt_3button_mouse
export PROFILE=30
IPADDR=192.168.123.2
NETMASK=255.255.0.0
NETWORK=192.168.0.0
BROADCAST=192.168.255.255
GATEWAY=192.168.123.1
DOMAIN=rw.sni.de
DNS_1=123.123.12.12
export PRINTER=printer-nana-deskjet
NETENV_SCRIPT=/etc/netenv/netenv_setup
XF86CONFIG_FILE=/etc/X11/XF86Config-crt

netenv_id=Laptop_at_home_crt_3button_mouse

netenv_id=This_string_must_contain_no_blanks_nor_special_characters

PROFILE=30

IPADDR=192.168.123.2
NETMASK=255.255.0.0
NETWORK=192.168.0.0
BROADCAST=192.168.255.255
GATEWAY=192.168.123.1
DOMAIN=rw.sni.de
DNS_1=123.123.12.12

Last not least this is the right place to define once and only once my printing environment:

export PRINTER=printer-nana-deskjet
export COLOR_PRINTER=printer-off-color-deskjet

if [ -r /tmp/netenv ]; then
. /tmp/netenv
fi

But what is this:

NETENV_SCRIPT=/etc/netenv/netenv_setup

Beware ! This is run during early stage of going multi user ! No network setup has been done yet ! It's done as root ! You have been warned !

So far legal terms and conditions. This is my script:

#!/bin/sh
# Simple way to configure the X-Server 
if [ -r $XF86CONFIG_FILE ]; then
    echo $XF86CONFIG_FILE will be used for configuring the X-Server ...
    mv /etc/X11/XF86Config /etc/X11/XF86Config.old
    ln -s $XF86CONFIG_FILE /etc/X11/XF86Config
fi

XF86CONFIG_FILE=/etc/X11/XF86Config-crt

Laptop_in_the_office

# Networkenvironment: Laptop at office (Network-Interface: Ethernet)
netenv_id=Laptop_at_office
PROFILE=31
IPADDR=123.123.35.134
NETMASK=255.255.255.0
NETWORK=123.123.35.0
BROADCAST=123.123.35.255
GATEWAY=123.123.35.1
DOMAIN=rw.sni.de
DNS_1=123.123.12.12
export PRINTER=printer-off-ps
export COLOR_PRINTER=printer-off-color-deskjet
NETENV_SCRIPT=/etc/netenv/netenv_setup
XF86CONFIG_FILE=/etc/X11/XF86Config-lcd

Other stuff

DNS

        # Update DNS stuff
        cp /etc/resolv.conf /etc/resolv.new
        echo "# $DEVICE begin" >> /etc/resolv.new
        test "$DOMAIN" && echo "domain $DOMAIN" >> /etc/resolv.new
        if [ "$DNSSRVS $DNS_1 $DNS_2 $DNS_3" != "   " ] ; then
            for DNS in $DNSSRVS $DNS_1 $DNS_2 $DNS_3 ; do
                echo "nameserver $DNS" >> /etc/resolv.new
            done
        fi
        echo "# $DEVICE end" >> /etc/resolv.new
        mv /etc/resolv.new /etc/resolv.conf

# Networkenvironment: Tower at home (Network-Interface: Plip)
export PROFILE=10
PLIP_START=yes
PLIP_IPADDR=200.0.0.1
PLIP_PARTNER=lulu
PRINTER=home-deskjet

Conclusion