Windows DNS and BIND Server together

Another one of my bulk DNS scripts.

This was a weird request however there were a number of requirements:

• Allow BIND servers running on Linux/Unix to take zone transfers of all production zones (forward and reverse), this should be limited to specific servers.
• BIND servers should only be allowed to request one transfers from specific servers
• Only authorised BIND servers should be permitted
• BIND servers SHOULD be listed in a name server query for a particular zone (that is, BIND servers should have an NS record)

The script is pretty simple:

Bulk import of DNS PTR Records

Due to a number of issues, I was once required to delete some reverse lookup zones in DNS and then recreate them. There were two reasons I had to do this, firstly there were some conflicting replications configurations, secondly I was merging some DNS servers and finally I was making the reverse look zones class B instead of 2 dozen class C zones.

Before I start, there is one limitation with this script. All of entries you are importing must belong to the same reverse lookup zone. For example, this script would handle importing entries of 10.0.0.23, 10.0.0.55 into a reverse lookup zone of 10.0.0.0/24 or even 10.0.0.0/16; however it will fail if you try to import those entries into a zone of 172.16.0.0/24.

This script I wrote for these sort of situations, and many others. Whenever doing this work, I have always had a resulting CSV file with my entries that I need to end up back in DNS. This file has had the following format:

host, ip

hostname1.domain.local, 10.0.0.1

hostname2.domain.local, 10.0.0.2

Once you have a CSV file of the above format, point the following code at it:

$filename = read-host "CSV filename"
$dnsserver = Read-Host "dnsserver"
$namespace = read-host "namespace - format 201.168.192.in-addr.arpa"
$entries = import-csv $filename
foreach ($entry in $entries) {
    dnscmd $dnsserver /recordadd $namespace $entry.ip "ptr" $entry.host
}

DNS Cleanup - Removing an old DNS Server

The script that is outlined below was written very quickly one night. The issue was we had several old decomissioned/dead DNS servers in the environment, and a lot of DNS namespaces to remove them from (aproximately 10 forward and 20 reverse lookup zones). It should be noted that this script assumes we can make a change on a single master server and replication (hopefully AD Integrated) will take care of the rest.

Enjoy.

$masterdns = "<Primary DNS FQDN>"

$olddnshost = read-host "Enter new host name (FQDN)"

$enumzones = get-WMIObject -Computer $masterdns -Namespace "root\MicrosoftDNS" `
    -Class "MicrosoftDNS_Zone"

foreach ($zone in $enumzones)
{
    if ($zone.zonetype -eq 1)
    {
        write-host ""
        $name = $zone.name

        dnscmd $masterdns /recorddelete $name "@" NS $olddnshost
       
        Write-Host "NS Record for "$olddnshost " deleted from "$name
    }

}

PowerShell DNS Week

The next few days worth of scripts will be focusing on PowerShell scripts which modify DNS.