doc/html/plugins/WindowsAuthentication.html
Support for cleartext authentication against a Windows domain or local Windows account.
plugin "WindowsAuthentication.dll" WindowsAuthentication "3ProxyAllowedGroup"
WindowsAuthentication.dll - location of the DLL; if the DLL is located in a different folder from 3proxy.exe, you must specify the complete path to the DLL here. 3ProxyAllowedGroup - the Windows system group allowed to use 3proxy. After the plugin is loaded, the 'windows' authentication type is supported. 4. Configure 'auth windows' for services that require Windows authentication. 5. It is recommended that you also configure authentication caching (see 'authcache') to prevent excessive workload on the domain controller. Example:
authcache user,pass 900
auth cache windows