#!/bin/bash

SOA=""
name="$1"

while [ -z "$SOA" ]
do
    SOA="$(dig SOA "$name" | awk '/^[^;].*SOA/{print $1}')"
    name="$(printf "%s" "$name" | sed 's/^[^.]\+\.//')"
    if [[ -z "$SOA" ]] && ! [[ "$name" =~ \. ]]
    then
        printf "Cannot find SOA for %s.\n" "$1" >&2
        exit 1
    fi
done
dig "@$(dig NS "$SOA" +short | head -n 1)" "$@"