#!/bin/bash

# change this to your dns resolver/cache server
DNS_IP=a.b.c.d

# the domain hint should be your ns servers
# if you have more than one your domain name
# should be sufficient
DOMAIN_HINT="domainname"

# the network hint should be the network your
# nameservers belong to
NETWORK_HINT="192.168.0"

# the following should be a list of exported domains
# one per line
NAMES=`cat named-export.txt`
for i in $NAMES
do
        RESULT=`dig @$DNS_IP -t NS $i +short`
        if D=`echo $RESULT | grep -v $DOMAIN_HINT`; then
                NS=`echo $RESULT | head -n 1`
                E=`dig -t A $NS +short`;
                if D=`echo $E | grep -v $NETWORK_HINT`; then
                        echo $i;
                fi
        fi
done