#!/bin/sh
 
#     [4.2.2] cronjob - DNS axfr based [host]

#   This is one  of many scripts  you could  use to accomplish  this task.  It
#   requires that your cron server have  AXFR privileges on your DNS  servers.
#   You could also use `host  -l` instead of `host  -t axfr` which will  allow
#   you to remove the  three `grep -v`  commands as well as  the `sed` at  the
#   end. Only  problem with  `host  -l` is  that it  will  not pick  up  CNAME
#   records, only A.
   
DOMAINS="unixdev.net colo.netizenweb.com bama.netizenweb.com netizenweb.com iridiumnetworks.net"
PREHOSTS="$HOME/.tcsh/hosts-pre"
HOSTS="$HOME/.tcsh/hosts"

(cat $PREHOSTS
 for each in $DOMAINS; do
      host -t axfr $each | grep -v ';' | grep -v Trying | grep -v Received | awk '{print $1}' | sed 's/\.$//'
 #    host -l $each | awk '{print $1}' ## when uncommented, comment above
 done
) | sort | uniq > $HOSTS