IvoryGate signs users in to existing WordPress accounts using an identity authenticated by Microsoft IIS Windows Authentication.

The plugin is designed for controlled Windows and IIS environments such as intranets. It does not implement Kerberos or NTLM itself and never receives or stores a Windows password. IIS performs Windows Authentication and provides the trusted server identity.

Key properties:

Exact, case-sensitive mapping from a Windows identity to an existing WordPress user ID.
No automatic user creation, role changes, or password changes.
HTTPS is required for automatic SSO.
Secure WordPress authentication cookies are created with the official WordPress API.
When SSO is enabled, WordPress password login and application passwords are disabled.
Unknown, missing, duplicated, or invalid mappings fail closed.
Optional logging contains fixed event codes only and does not include identities, cookies, passwords, or request data.
Existing WordPress sessions are not switched to another account.

Important requirements

IvoryGate requires:

Microsoft IIS with Windows Authentication using Negotiate, NTLM, or Kerberos.
A server configuration in which IIS securely sets REMOTE_USER, AUTH_USER, and AUTH_TYPE.
HTTPS for the request, WordPress Address, and Site Address.
Existing WordPress user accounts to map to.
A single-site WordPress installation. WordPress Multisite is not supported.

IIS may reject a request with HTTP 401 before WordPress or IvoryGate runs. In that case, the browser may show its own Windows credentials dialog. A WordPress plugin cannot replace that dialog or reliably detect private or incognito browsing mode.

IvoryGate does not trust identity values from HTTP_REMOTE_USER, X-Forwarded-User, Authorization, cookies, or other client-controlled headers.

Lockout protection

Before enabling SSO, retain administrative access to the server files.

To restore native WordPress login during recovery, add the following before WordPress loads:

define( ‘IVORYGATE_DISABLE_SSO’, true );

You can also disable the plugin by renaming its directory from the server file system. The plugin intentionally retains its settings when deactivated or uninstalled.

Privacy

IvoryGate does not transmit data to external services. Configuration is stored in the local WordPress options table. It contains explicit Windows identity strings and WordPress user IDs entered by an administrator.

Optional diagnostic logging writes only fixed event codes to the operating system log through PHP syslog. It does not log identities, passwords, cookies, tokens, exception messages, or request data.