Background on the DNS issue faced
There are times when DNS split horizon is required to point an ‘A’ record to an internal address however this normally requires you to duplicate every record in the zone on the internal DNS server. For example autodiscover.company.com without needing the whole domain of company.com being duplicated on the internal DNS servers.
An example of an external zone for a company:
| Record Type | Host | Address |
|---|---|---|
| A | www | 88.55.44.22 |
| A | 88.55.44.23 | |
| A | remote | 88.55.44.60 |
The normal approach for split dns requires you to duplicate all the entires in the zone on your internal DNS server. This is risky with changes to the public zone not always being updated on the internal zone. An example of an internal required zone design:
| Record Type | Host | Address |
|---|---|---|
| A | www | 88.55.44.22 |
| A | 88.55.44.23 | |
| A | remote | 10.0.40.2 |
The table above show how an internal zone allows for internal clients to use an internal IP address for the host name of “remote.company.com”.
The Easy Solution
If you have internal Windows Server 2012 or higher there is a easy to achieve the same results without having to duplicate all the entires. This creates a zone and with the same name as the record for the DNS entry you are pin pointing.
First step is the creation of a DNS zone for the hostname (not the domain name zone!) with powershell command:
Add-DnsServerPrimaryZone -Name remote.company.com -ReplicationScope Forest
The second step creates a record type of ‘A’ with the same name as the DNS zone:
Add-DnsServerResourceRecordA -IPv4Address 10.0.40.2 -ZoneName remote.company.com -Name remote.company.com
The much long version of how to configure this feature can be found here: https://blogs.technet.microsoft.com/undocumentedfeatures/2016/07/08/creating-a-pinpoint-dns-zone/
