gistfile1.pl

#!/bin/bash
debug=''
debug=''
is_dead_ping()
{
#  echo "is_dead_ping $1 ?"
  ping -c 1 $1 > /dev/null
  if [ $? -ne 0 ]; then
#    echo $1 is down 
    return 0
  else
    return 1
  fi
}

for i in 192.118.70.{1..255} 
#for i in 10.200.92.{21..41} 
#for i in   192.168.50.{220..249}
do
  is_dead_ping $i
  if [ $? -eq 0 ] 
    then
    j=`echo $i | sed 's/118/168/g'`
#   echo "  $i Free! Now $j"
    is_dead_ping $j
    if [ $? -eq 0 ]
    then
      echo "    ****  IP networks are free: $i and $j"
    fi
  fi
done