#!/bin/bash
#
# Suitable for (at least) RedHat Enterprise Linux 6.
#
# Put this file, with executable permission in
#   /etc/NetworkManager/dispatcher.d 
# with a name such as 
#  90-say-hello
# in order to have it run on each change of an interface.
#

# interface name: e.g. eth0, wlan0 
IF=$1  

# 2nd arg: status: can be:  up, down, pre-up, post-down 
CH=$2


# leave a log message on a webserver, so that we can find the time and 
# apparent ip address for every time that the interface changes
wget http://gnu.ets.kth.se/hello_from_$(hostname)_${IF}_${CH}.ping -a /var/log/ifup_last.log -O /dev/null