This project provides a set of daemons to manage access to remote
directories and authentication mechanisms, it provides an NSS and
PAM interface toward the system and a pluggable backend system to
connect to multiple different account sources. It is also the
basis to provide client auditing and policy services for projects
like FreeIPA.  sssd also features caching, which can allow for
offline use to assist laptop users.

WWW: https://fedorahosted.org/sssd/