Manual DNS Entries for Microsoft KMS Volume Activation

In my imaginary domain, I have my KMS Server running at 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 "" -DomainName "" -Priority 0 -Weight 0 -Port 1688

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

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

    You can (obviously) use a FQDN instead of 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 SRV service location:
         priority       = 0
         weight         = 0
         port           = 1688
         svr hostname   =
  3. Ensure you have monitoring for your KMS hosts by verifying that tcp/1688 is responding at in my example.