In %TRIDION_HOME%\web\web.config, configure an HTTP module that can handle single sign-on requests.
<add name="SsoAgentHttpModule" type="Tridion.Security.Web.SsoAgentHttpModule, Tridion.Security, Version=7.1.0.52, Culture=neutral, PublicKeyToken=ddfc895746e5ee6b" />
Configuring single sign-on in the Editors' Themes\ folders
Configuring single sign-on in the webservices\ folder
Configuring single sign-on in the web\WebUI\WebRoot\ folder
Configuring single sign-on for Device Preview
Configuring single sign-on for UGC
Setting up IIS for anonymous access