A quick little script to automatically enable Firestarter[1] when Network Manager[2] enables an interface. This is for Ubuntu/Breezy or bleeding edge Debian. Put it in /etc/NetworkManager/dispatcher.d

#!/bin/sh

source /etc/firestarter/configuration 2>&1

# Check to see if the interface that changed is the one currently
# protected by firestarter. If not, quit.
[ "$1" != "$IF" ] && exit

# Check the current status of Firestarter
[ -e /var/lock/subsys/firestarter -o -e /var/lock/firestarter ]
fs_status=$?

case "$2" in
        up)
                [ "$fs_status" -gt 0 ] && /etc/init.d/firestarter start
        ;;
        down)
                ## Uncomment the following line to allow this script to
                ## turn off the firewall when the interface goes down.
                #[ "$fs_status" -eq 0 ] && /etc/init.d/firestarter stop
        ;;
esac

By default it does not disable the firewall when the interface goes down because I prefer to do that myself. [1] http://packages.debian.org/stable/source/firestarter, http://fs-security.com/
[2] http://packages.debian.org/unstable/virtual/network-manager , http://www.gnome.org/projects/NetworkManager/