#!/bin/sh

# POSIX SH shell script to display the IP Address - one that the machine has, 
# as well as router's public IP Address, if any.

# First written : S Gowtham,  Wed Dec 28 22:05:35 EST 2005
# Last modified : S Gowtham,  Fri Dec 30 06:57:50 EST 2005
#                 S Gowtham,  Tue Jan  3 09:52:47 EST 2006
#                 Jon DeVree, Tue Jan  3 22:28:15 EST 2006 
#                             (jadevreeNOSPAM@mtu.edu)

# Questions/Comments must be sent to mail@sgowtham.net

IFACE=`netstat -rn | grep ^0.0.0.0 | awk '{print $8}'`

if [ "$IFACE" = "" ];
then
  echo
  echo " You are not connected to the internet"
  echo
  exit 0
fi

IP=`/sbin/ifconfig $IFACE | grep Bcast | awk '{print $2}' | awk -F ':' '{print $2}'`
NSIP=`curl -s http://checkip.dyndns.org | awk '{print $6}' | awk -F '<' '{print $1}'`

if [ "$IP" = "$NSIP" ];
then
  echo
  echo " Your machine is directly connected to the internet"
  echo " IP Address : $IP"
  echo
else
  echo
  echo " Your machine is configured behind a router"
  echo " Machine's static IP Address : $IP"
  echo " Router's  public IP Address : $NSIP"
  echo
fi