Publisher Summary The chapter discusses Samba and NFS file-sharing subsystems from a security standpoint. Network file system (NFS) sub-system is a widely used protocol that allows computers to share files over a network. The implementation on the HP Non-Stop Server is based on the one developed by Sun Microsystems. It allows PCs or other network hosts to create or use files on the Non-Stop Server via TCP/IP over a LAN.. The NFS subsystem is made up of several NFS servers, NFS LAN server, NFS configuration files, NFS user id files, and RPC port-map. It also provides a review of various object files used by NFS: like NFS-CONV is the object file for the NFS Configuration Quick-start Utility, which is used to configure the NFS subsystem on the Non-Stop Server; NFS-MGR is the object file for the NFS manager program, $ZNFS, which accepts commands, reports errors, and generates event messages. Access to NFS files is checked in three stages: Translation of the user's NFS userid to a Guardian userid, user access to the Export object (fileset); and each NFS operation on a specific NFS file. The chapter also details Samba that provides file and print services for Microsoft Windows clients, and its implementation by HP NonStop Server implementation, which is a freeware. The only way to protect a system from misuse of its resource by Samba users is to secure every file so that only the appropriate users can access it.