#! /bin/bash
# All ip/host name list
bcast=`/sbin/ifconfig |sed -e '/Bcast/{s/^.*Bcast://;s/Mask.*$//p}' -n`
echo "Broadcast address ${bcast}"
ping -c4 -b $bcast >/dev/null 2>&1
/sbin/arp -a 2>/dev/null |
  awk  '{
	sub("^.+[(]","");sub("[)].*$","");
	ip=$0;
	split( ip, ot, "." );
	printf "%03d.%03d.%03d.%03d:%s\t",ot[1],ot[2],ot[3],ot[4],ip;
	cmd = sprintf("dig -x %s", ip);
	while( cmd | getline ){
		if( /^;/ ) { continue; };
		if( /PTR/) { print $NF; };
	}
  }' |
sort -n | cut -d: -f2-