ips_for_fqdn

#!/bin/bash
FQDN=$1
if [ "$FQDN" == '' ]; then echo 'Pass FQDN along.' >&2; exit 1; fi

DOMAINNAME=$(
  echo $FQDN | sed 's/\.$//' | awk -F. '{print $(NF-1)"."$(NF)}'
)

NAMESERVERS=$(
  dig NS $DOMAINNAME +short | sed 's/\.$//' | sort | uniq
)

CNAMES=$(
  for NAMESERVER in $NAMESERVERS
  do
    dig CNAME $FQDN @${NAMESERVER} +short
  done | sort | uniq
)

IPS_A=$(
  for NAMESERVER in $NAMESERVERS
  do
    dig A $FQDN @${NAMESERVER} +short
  done | sort | uniq
)

IPS_CNAME=$(
  for NAMESERVER in $NAMESERVERS
  do
    dig A $CNAME @${NAMESERVER} +short
  done | sort | uniq
)

IPS=$(
  (echo $IPS_A; echo $IPS_CNAME) | sort | uniq
)

echo 'FQDN:'
echo $FQDN
echo
echo 'DOMAINNAME:'
echo $DOMAINNAME
echo
echo 'NAMESERVERS:'
for NAMESERVER in $NAMESERVERS
do
  echo $NAMESERVER
done
echo
echo 'CNAMES:'
for CNAME in $CNAMES
do
  echo $CNAME
done
echo
echo 'IPS_A:'
for IP_A in $IPS_A
do
  echo $IP_A
done
echo
echo 'IPS_CNAME:'
for IP_CNAME in $IPS_CNAME
do
  echo $IP_CNAME
done
echo
echo 'IPS:'
for IP in $IPS
do
  echo $IP
done
echo