Shell Script To Check A Record For Given Domain or Hostname On All Nameservers

#!/bin/bash


# Shell script to check A record for given domain or hostname on all Nameservers


# -------------------------------------------------------------------------


# Copyright (c) 2002 nixCraft project <http://cyberciti.biz/fb/>


# This script is licensed under GNU GPL version 2.0 or above


# -------------------------------------------------------------------------


# This script is part of nixCraft shell script collection (NSSC)


# Visit http://bash.cyberciti.biz/ for more information.


# -------------------------------------------------------------------------


# How do I use this script?


# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


# ./script nixcraft.net 3 cyberciti.biz ns


# where,


# * nixcraft.net  - nameserver domain name


# * 3  - total number of nameserver


# * cyberciti.biz  - Domain name to check for A record


# * ns - nameserver domain prefix, so ns becomes ns1.nixcraft.net,ns2.nixcraft.net,ns3.nixcraft.net


# It will check cyberciti.biz domain on all 3 nameservers i.e. ns{1,2,3}.nixcraft.net


# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


# Note: Only tested on GNU/Linux but should work under BSD / UNIX like oses.


# Last updated on: Jul-30-2008: Added failsafe and nameserver test.


#-----------------------------------------------------------------------


DOMAIN="$1"  # nameserver domain


MAX="$2" # query ns


AREC="$3" # domain or hostname to check against given nameserver


NS="$4"


 


# make sure we get args


if [ ! $# -ge 3 ]


then


        echo "$(basename $0) nameserver-domain number-of-nameservers domain-name-to-check nameserver-domain-prefix"


        echo "Example: Check domain viveks.org on all 3 nameservers ns1.nixcraft.net, ns2.nixcraft.net, ns2.nixcraft.net, enter:"


        echo "$(basename $0) nixcraft.net 3 viveks.org"


        exit 1


fi


 


# shell array to hold all A records


IPArray[0]=0


 


# failsafe


[ "$4" == "" ] && NS="ns"


 


# note seq may not be available on other UNIX like oses


for n in $(seq 1 ${MAX})


do


        # build nameserver name


        thisNs="${NS}${n}.${DOMAIN}"


        # make sure nameserver exits


        host $thisNs | grep "NXDOMAIN" >/dev/null


        if [ $? -eq 0 ]


        then


                echo "Nameserver $thisNs does not exits..."


                exit 2


        fi


        # get output


        out=$(host $AREC $thisNs | grep address)


        # get A record


        IPArray[$n]=$(echo $out | awk '{print $4}')


        [ "$out" != "" ] && echo "${out} [$thisNs]"


done


 


firstIp="$(echo ${IPArray[1]})"


isARecSame=0


 


# use for loop to see all A records


for (( i=1; i<=$MAX; i++ ));


do


  [ "$firstIp" !=  "${IPArray[$i]}" ] &&  isARecSame=1 || :


done


 


[ $isARecSame -eq 1 ] && echo "Warning: A record is not matching on all nameserver(s)" || :