Command Line and Scripting in all their glory!!

Challenge: You are asked to update ~500 records on your DNS servers running Windows 2003 SP1.

Solution : Spend hours and hours updating the entries using the pretty MMC based GUI
use some creative scripting to do the work for you. Here is the recipe

1) Download the Windows Support Tools for SP1 from here. The support tools contain a useful utility called “dnscmd”. The tool allows one to add/update/delete entries for Windows DNS servers through a command line interface. DnsCmd /help returns the following

Usage: DnsCmd []:
IP address or host name — remote or local DNS server
. — DNS server on local machine
/Info — Get server information
/Config — Reset server or zone configuration
/EnumZones — Enumerate zones
/Statistics — Query/clear server statistics data
/ClearCache — Clear DNS server cache
/WriteBackFiles — Write back all zone or root-hint datafile(s)
/StartScavenging — Initiates server scavenging
/ResetListenAddresses — Set server IP address(es) to serve DNS requests
/ResetForwarders — Set DNS servers to forward recursive queries to
/ZoneInfo — View zone information
/ZoneAdd — Create a new zone on the DNS server
/ZoneDelete — Delete a zone from DNS server or DS
/ZonePause — Pause a zone
/ZoneResume — Resume a zone
/ZoneReload — Reload zone from its database (file or DS)
/ZoneWriteBack — Write back zone to file
/ZoneRefresh — Force refresh of secondary zone from master
/ZoneUpdateFromDs — Update a DS integrated zone by data from DS
/ZonePrint — Display all records in the zone
/ZoneResetType — Change zone type
/ZoneResetSecondaries — Reset secondary\notify information for a zone
/ZoneResetScavengeServers — Reset scavenging servers for a zone
/ZoneResetMasters — Reset secondary zone’s master servers
/ZoneExport — Export a zone to file
/ZoneChangeDirectoryPartition — Move a zone to another directory partition
/EnumRecords — Enumerate records at a name
/RecordAdd — Create a record in zone or RootHints
/RecordDelete — Delete a record from zone, RootHints or cache
/NodeDelete — Delete all records at a name
/AgeAllRecords — Force aging on node(s) in zone
/EnumDirectoryPartitions — Enumerate directory partitions
/DirectoryPartitionInfo — Get info on a directory partition
/CreateDirectoryPartition — Create a directory partition
/DeleteDirectoryPartition — Delete a directory partition
/EnlistDirectoryPartition — Add DNS server to partition replication scope
/UnenlistDirectoryPartition — Remove DNS server from replication scope
/CreateBuiltinDirectoryPartitions — Create built-in partitions

As you can see, there is ton of stuff you can do with this utility. I am mainly interested in the /RecordAdd function for this example.

2) Write a small perl script to massage your raw data into the form you want. In this case, I was given the hostname and the IP address in an excel spreadsheet. I exported the spreadsheet to a command delimited file and the following perl script finished the job for me

#!/usr/bin/perl -w
# use strict;
my (@File, @Column, @HostID, @NetworkID, $Line);
my $infile = ‘NetworkCore.csv’;
my $outfile = ‘NetworkCore_Processed.txt’;

or die “Couldn’t open $infile for reading: $!\n”;
@File = ;
close READ;

or die(“Unable to open my $outfile: $!”);

foreach $Line(@File)
@Column = split(/,/,$Line);
@NetworkID = split(/\./, $Column[0]);
@HostID = split(/\./, $Column[1]);
print OUTPUT “dnscmd DNS_SERVER /RecordAdd DOMAIN_TO_ADD $HostID[0] A $Column[0]\n”;
print OUTPUT “dnscmd DNS_SERVER /RecordAdd $NetworkID[3].$NetworkID[2] PTR $Column[1]\n”;
close OUTPUT

Note : The DNS_SERVER, DOMAIN_TO_ADD and need to be replaced with your own values

3) Open a command prompt on the DNS server and copy and paste the contents of the file that the perl file spits out.. Did, I say that I love technology?? :)..