---
title: "Windows back-end authentication"
slug: "oas-ag-windows-back-end-authentication-3-27"
updated: 2025-07-04T10:04:40Z
published: 2025-07-07T14:23:08Z
canonical: "docs.onespan.com/oas-ag-windows-back-end-authentication-3-27"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.onespan.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Windows back-end authentication

OneSpan Authentication Server can authenticate Windows users via Windows or LDAP Active Directory back-end authentication:

- Windows back-end authentication should be used if OneSpan Authentication Server is installed on a Windows machine that is a member server of the Windows domain.
- LDAP back-end authentication may be used if OneSpan Authentication Server is installed on a machine that is either not a member server of the Windows domain or running a Linux operating system.

To allow users to authenticate with user names in different formats, OneSpan Authentication Server identifies user accounts via user ID and domain. For an overview of user ID and domain resolution for Windows back-end authentication, see [Windows user name resolution](/sec/docs/oas-ag-windows-user-name-resolution-3-27).