#!/usr/bin/perl
#
# Simple script to update entries in DNS based on the premise that
# the DNS server you are targeting allows entries to be updated dynamically.
#
# Jon Hart <jhart@spoofed.org>
use diagnostics;
use Net::DNS;
$SERVER=$ARGV[0] or &usage;
$DOMAIN=$ARGV[1] or &usage;
$RECORD=$ARGV[2] or &usage;
$ENTRY=$ARGV[3] or &usage;
my $res = Net::DNS::Resolver->new;
$res->nameservers($SERVER);
$packet = Net::DNS::Update->new($DOMAIN);
$packet->push(update => rr_add("$RECORD $ENTRY"));
my $reply = $res->send($packet);
if ($reply) {
   if ($reply->header->rcode eq 'NOERROR') {
      print "Update succeeded\n";
   } else {
      print "Update failed: ", $reply->header->rcode, "\n";
   }
} else {
   print "Update failed: ", $res->errorstring, "\n";
}
sub usage {
   print<<EOF;
   Usage:
   $0 <DNS Server> <domain> <domain record to add/update> <data to add>
   Examples:
   # add forward DNS (A record)
   $0 10.0.0.1 yourdomain.com test "60 A 10.0.0.5" 
   # add reverse DNS (PTR record), untested 
   $0 10.0.0.1 yourdomain.com 10.0.0.5 "60 PTR test" 
EOF
   exit(1);
}