Manual DNS Entries for Microsoft KMS Volume Activation

In my imaginary domain ipsum.justinho.com, I have my KMS Server running at 10.10.10.21. While the KMS Server can auto publish DNS entries, I also have a few satellite sites that I link across a VPN, that I want local-to-the-site DNS servers to respond to.

1. On the DNS Server, I add the VLMCS SRV record.

   Using Powershell, on a Windows Server this becomes: ¹²

   Add-DnsServerResourceRecord -Srv -Name "_VLMCS._tcp" -ZoneName "ipsum.justinho.com" -DomainName "10.10.10.21" -Priority 0 -Weight 0 -Port 1688

   On an Ubiquiti EdgeRouter, using dnsmasq, this becomes: ³

   set service dns forwarding options srv-host=_VLMCS._tcp,10.10.10.21,1688

   You can (obviously) use a FQDN instead of 10.10.10.21 and load balance across a few hosts as well.

2. Then on client machines, I verify the DNS entry is present/resolving correctly, using:

   nslookup -type=srv _vlmcs._tcp

   which returns

    _vlmcs._tcp.ipsum.justinho.com SRV service location:
        
        priority       = 0
        weight         = 0
        port           = 1688
        svr hostname   = 10.10.10.21
   

3. Ensure you have monitoring for your KMS hosts by verifying that tcp/1688 is responding at _vlmcs._tcp.ipsum.justinho.com in my example.