# Welcome to the Authentication Service SSO Documentation!
This 4App is an extension for 4App Authentication Provider LDAP. It allows to download the required web service for SSO and gives installation instructions.
The web service enables single sign-on (SSO) for Windows Active Directory (AD) users. Users logged in to the Windows domain will be logged in to the 4ALLPORTAL automatically.
Please note: This application needs to run on a Windows Server connected to the domain for which SSO should be processed.