NFS is available on all variants of UNIX. Many third-party solutions for NT also offer NFS. This widely used tool lets users locally share file systems on foreign hosts. NFS accomplishes file sharing by exporting a shared file system to a specified server. The NFS server then mounts the file system so that it looks as if it were local to users. Using NFS can create security problems because after NFS mounts a network file system, that system is open to any user with the proper permissions. Therefore, abuse is possible. If you use NFS, we recommend that you enable all its security features (e.g., restricted read and write permissions). In addition, you need to properly manage user and group permissions. Further, we recommend that you export only those file systems that users require. Another approach to secure file sharing is to use the broadcast-oriented methods that Microsoft's Server Message Block (SMB) supports to communicate resources. The Common Internet File System (CIFS) on UNIX systems is an extension of SMB. SMB technology is also available for other client platforms, including VMS and Macintosh. Samba is freeware that uses SMB to permit file system sharing between UNIX and NT systems. However, you need to be careful when using Samba or any other SMB technology. SMB uses NetBIOS to broadcast file information; thus, DOS- and Windows-based users can use NET VIEW, NET USE, and similar utilities to access resources. If you haven't set proper permissions, you might be undermining your network's security.