DNS SPF Expander (MAX LOOKUP should not exceed 10 lookups)

dns_spf_expander.sh

#!/bin/bash

#TO RUN
# > ./dns_spf_expander.sh domain.com

lookup_count=0
function spf_expand {
	for spf in $1 ; do
		if echo $spf | grep "include:" > /dev/null 2>&1 ; then
			((lookup_count++)) 
			temp_spf=`echo $spf | awk -F"include:" '{print $2}'`
			temp_results=`/usr/bin/nslookup -q=TXT "$temp_spf" 8.8.8.8 | grep text`
			echo "Lookup $lookup_count: $temp_spf"
			if echo $temp_results | grep "include:" > /dev/null 2>&1 ; then		
				spf_expand "${temp_results}"
			fi
		fi
	done

}

lookup_spf=`dig txt $1 | grep "v=spf1" | awk -F"\"" '{print $2}'`
echo "$1 SPF record is \"$lookup_spf\""
spf_expand "${lookup_spf}"
echo "SPF DNS LOOOKUP Count = $lookup_count"