#!/bin/bash

function get_domain_entry {
	IFS='.' read -r -a domain <<< "$1"
	NS="8.8.8.8"
	count=0
	pendingdomain=""
	for i in `printf '%s\n' "${domain[@]}"|tac`; do
		count=$((count+1))
		pendingdomain="${i}.${pendingdomain}"
		for j in $NS; do
			NEXTNS=`dig @${j} +timeout=1 +time=1 +tries=2 +noall +authority +answer ${pendingdomain} NS | awk '{if($4 == "NS") {print $5}}' | tr '\n' ' ' | sed -e '/^;;/d'`
			if [ -n "$NEXTNS" ];then
				NS=$NEXTNS
				break
			fi
		done
		if [ "$count" == "${#domain[@]}" ]; then
			for j in $NS; do
				rawresult=`dig @${j} +timeout=1 +time=1 +tries=2 +noall +authority +answer ${pendingdomain} A ${pendingdomain} AAAA | sed -e '/^;;/d'`
				CNAME=`echo "$rawresult" | awk '{if($4 == "CNAME") {print $5}}' | head -n 1`
				ENTRY=`echo "$rawresult" | awk '{if($4 == "A" || $4 == "AAAA") {print $5}}'`
				if [ -n "$ENTRY" ]; then
					echo "$ENTRY"
					break
				elif [ -n "$CNAME" ]; then
					ENTRY=`get_domain_entry "$CNAME"`
					echo "$ENTRY"
					break
				fi
			done
		fi
	done
}
result=`get_domain_entry $1`
echo $result | tr '\n' ' '