The Client Authentication Add-on reduces management costs and lowers server and application load. It checks all user certificates using the Online Certificate Status Protocol (OCSP). The F5 BIG-IP Advanced Client Authentication Add-on also prevents unwanted traffic from reaching your servers and applications and supports the Pluggable Access Module (PAM) for passing client information to external devices and authenticating it. The module gives companies the freedom to integrate BIG-IP into any type of verification device that accepts PAM.