#!/bin/bash
#
# Author:   deelkar@gmx.de
#
# Script:   /usr/local/bin/reversedns
#
# Version:  7.3.1
#
# Requires: Bash, grep, sed, host
#
# Public:   yes

# Copyright (C) 2002 "Dirk-Lueder Kreie" <deelkar@gmx.de>
#
# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the Free
# Software Foundation; either version 2 of the License, or (at your option)
# any later version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
# more details.
#
# You should have received a copy of the GNU General Public License along with
# this program; if not, write to the
#
# Free Software Foundation, Inc.
# 59 Temple Place, Suite 330
# Boston, MA 02111-1307
# USA.


dyndns=$1

if [ "$1" = "" ]; then
  dyndns="127.0.0.1"
fi

myhost=`host $dyndns|grep "pointer"`

if [ "$myhost" = "" ]; then
  pushd /var/log/arp >/dev/null
  grep $1 $(ls -t /var/log/arp) | sed -e 's/.*log://' | sed -n 1p  | sed -e 's/\([0-9]*\.[0-9]*\.[0-9]*\.[0-9]*\).*\([[:alnum:]][[:alnum:]]:[[:alnum:]][[:alnum:]]:[[:alnum:]][[:alnum:]]:[[:alnum:]][[:alnum:]]:[[:alnum:]][[:alnum:]]:[[:alnum:]][[:alnum:]]\).*/\1 (\2)/' -e 's/[^[:alnum:]]*\*.*MP.*eth0/ (pptp)/' 
  popd >/dev/null
fi

for dyndnsprovider in 3-a.net. ath.cx. ddns.us. no-ip.org. de. lan.; do
for IP_PARAM in $myhost; do
  echo $IP_PARAM | grep -i ${dyndnsprovider} | sed 's/\.[a-z-][a-z-]*\.'${dyndnsprovider}'$//' 
done;done | head -n1