I've written a script that will turn my laptop into an instant gateway if I have a connection on the lan port. It uses dnsmasq for dns forwarding and DHCP while iptables provides the forwarding/masquerading for ip.

I use this for providing my Nokia 770 a link when I only have a wired connection, or when I want to ssh into my Nokia 770.

#!/bin/sh
#
# Requires: dnsmasq, iptables debian packages

function start () {
  ifdown --force eth1
  ifconfig eth1 10.2.5.2 netmask 255.255.255.0
  iwconfig eth1 mode ad-hoc
  iwconfig eth1 essid maemo
  /etc/acpi/ibm-wireless.sh on
  iptables -F
  iptables -t nat -F
  iptables -t mangle -F
  iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
  echo 1 > /proc/sys/net/ipv4/ip_forward
  /etc/init.d/dnsmasq start
}

function stop () {
  /etc/acpi/ibm-wireless.sh off
  ifdown --force eth1
  iptables -F
  iptables -t nat -F
  iptables -t mangle -F
  echo 0 > /proc/sys/net/ipv4/ip_forward
  /etc/init.d/dnsmasq stop
}

case "$1" in
  start)
    start
    ;;
  stop)
    stop
    ;;
  restart)
    stop
    start
    ;;
  *)
    echo "Usage: maemo {start|stop|restart}" >&2
    exit 1
    ;;
esac

exit 0

So using fglrx and selecting the mirror config from fglrx-config I was able to get my computer working with my DVI monitor such that I can unhook my laptop from the port replicator and dynamically readjust my resolution from 1600x1200 to the laptop display's 1400x1050 size. Initially I had to manually change resolutions by executing xrandr and FvwmCommand from a terminal. Now I've gotten it down to a small script. Yay for learning awk and sed . . .

#!/bin/bash
lcd=`xrandr|awk '/1400 x 1050/ {print $1}'|sed 's/*//'`
dvi=`xrandr|awk '/1600 x 1200/ {print $1}'|sed 's/*//'`

res=`xrandr|awk '/*/ {print $2 "x" $4}'`

if [[ $res = '1600x1200' ]]; then
  xrandr -s $lcd
  FvwmCommand 'Restart'
else
  xrandr -s $dvi
  FvwmCommand 'Restart'
fi

I would eventually like to have udev/hotplug/whatever thinger automatically detect when the monitor is connected and switch resolutions right then and there.

I would also like to make it so that I don't have to use the X11 output driver for media so that I can watch movies on the external display.

In other news, I enabled the experimental features of ibm-acpi so that I can use fanctrld