Microsoft Office 365: Kms //top\\

| | Best For | Requires Internet | | --- | --- | --- | | KMS | Large on-prem networks, air-gapped environments | Only for host activation | | MAK (Multiple Activation Key) | Smaller volume deployments | Per activation | | Active Directory-Based Activation (ADBA) | Domain-joined PCs without KMS host | No | | User-Based Subscription | Roaming users, hybrid work | Yes (periodic) | | Cloud Trust | Modern managed devices (Intune) | Yes |

Microsoft Office 2016 and Office 2019 reached end of support on October 14, 2025 . Microsoft no longer provides security patches, bug fixes, or technical support for these versions. Users are strongly recommended to migrate to subscription-based Microsoft 365 services to avoid security risks.

Managing software licensing for hundreds or thousands of users is a daunting task. For organizations that use volume-licensed versions of Microsoft Office, the Key Management Service (KMS) offers an efficient, automated solution to activate Office across an entire network without requiring individual product keys or constant internet connectivity.

The KMS host was a lonely sentinel. It sat on a server, listening on TCP port 1688. Its job was to wait for clients—laptops, desktops, tablets—to reach out and say, "I need to be activated." The host would check its count. If enough unique machines had knocked on the door in the last 30 days, the host would issue a confirmation. "You are recognized. You are activated." microsoft office 365 kms

Furthermore, MAK keys are tied to a specific hardware ID. If you reinstall Windows, that counts as using one of your MAK activations. While MAK is simple to set up for a small number of devices, it is not as scalable or manageable for large fleets. KMS avoids this issue entirely, as KMS activations are not "used up" in this way, making it the superior choice for managing laptop fleets that are frequently reimaged. For more information on converting from MAK to KMS, consult the official Microsoft Volume Activation documentation.

| Option | Features | Compatibility | |--------|----------|----------------| | | Free with OneDrive; Word, Excel, PowerPoint in browser | Limited offline use | | LibreOffice | Full office suite; supports .docx, .xlsx | 100% free, open-source | | Google Workspace (free) | Docs, Sheets, Slides – collaborative | Cloud-based | | WPS Office Free | Similar interface to Microsoft Office | Includes ads | | OnlyOffice | Strong compatibility with MS formats | Desktop and cloud |

By default, volume-licensed Office clients with preinstalled GVLKs automatically discover the KMS host by querying DNS for SRV resource records that publish the KMS service (specifically, records). When the KMS host is installed and a key is entered, it registers itself in DNS by adding a _VLMCS record. This auto-discovery mechanism eliminates the need for manual configuration on each client. | | Best For | Requires Internet |

By default, the volume-licensed edition of Office on a client computer will attempt to locate a KMS host on the local network via DNS. It does this by searching for a Service (SRV) resource record (RR) named _VLMCS._tcp that is published by the KMS host.

Many enterprises use Microsoft 365 cloud services but deploy on specific machines. This includes restricted workstations, factory floors, or secure defense networks lacking internet access. Administrators deploy Office LTSC via the Office Deployment Tool (ODT) and configure their local KMS server to handle the activations. Shared Computer Activation (SCA)

You can configure whether the last used KMS host computer is saved to the cache on the KMS client: Managing software licensing for hundreds or thousands of

Disclaimer: This article explains the technical configuration of KMS for legitimate enterprise volume licensing scenarios.

. To stay activated, the client must reconnect to the KMS host at least once every 7 days to renew its lease. Why Use KMS for Office 365? Offline Activation