#!/bin/bash

TEST=$1

if [[ "${TEST:0-1}" != '.' ]];then
	TEST=$TEST. ## add dot	
fi

IPS=$(dig ${TEST} a ${TEST} aaaa +short)

echo IPS: $IPS
if [[ $IPS == "" ]]; then
	echo No IPs
	exit -1
fi

while IFS= read -r ipline
do
   RESULT=$(dig -x $ipline +short)
	if [[ "$RESULT" == "$TEST" ]]; then
		echo Success Forward/Reverse
		echo " " $TEST =\>
		echo " " $ipline =\>
		echo " " $RESULT
		
	else
		echo FAILED FORWARD/REVERSE 
		echo " " $TEST =\>
		echo " " $ipline =\>
		echo " " $RESULT
		
	fi

done < <(printf '%s\n' "$IPS")

	
$ ./script.sh dns.google
IPS: 8.8.4.4 8.8.8.8 2001:4860:4860::8888 2001:4860:4860::8844
Success Forward/Reverse
  dns.google. =>
  8.8.4.4 =>
  dns.google.
Success Forward/Reverse
  dns.google. =>
  8.8.8.8 =>
  dns.google.
Success Forward/Reverse
  dns.google. =>
  2001:4860:4860::8888 =>
  dns.google.
Success Forward/Reverse
  dns.google. =>
  2001:4860:4860::8844 =>
  dns.google.