8.1 Basic Networking Knowledge
8.1.5 The directory services of the major network operating systems
Windows NT 

With multiple servers, in the past, Windows NT required a domain, where users were assigned a password to each domain. To maintain all the passwords, the domain controller was created to allow users to have one password and be able to have access to all the resources on all the servers.

The domain controller manages user access to the network and stores the security account information into a common security database, called the Security Access Manager (SAM). SAM verifies passwords, enables users to store and secure information, and searches for information on the network. When a user has successfully logged into the database, the domain controller issues the user an access token. Access tokens allow users to access any service without having to type in each password.

Novell NetWare

Novell NetWare 3.x relies on a security database, called the Bindery, which uses only IPX/SPX. NetWare 4.x and 5.x relies on Novell Directory Services (NDS), which is a built in directory service that uses TCP/IP or IPX/SPX. NDS is based on the Internet Directory Standard X.500, which uses a resource called the NDS tree to organize all user and resource information. The NDS tree allows users to log into the network and have the ability to access any of the resources, which are available.

UNIX

The UNIX directory services use a file system called the Network File System (NFS), which is similar a DOS file system. This NFS grants users permission to certain parts of the file system and controls the security of the UNIX systems. Because the shared files are transparent, users using NFS are able to view and edit files on other UNIX hosts.

UNIX systems can also use Microsoft Clients and servers using SAMBA to have the ability to communicate with Server Message Block (SMB). Because UNIX connects to the Windows Network running SMB, Microsoft clients and servers view the UNIX as if it were another Windows client. UNIX also uses DNS to resolve Transport Layer names into logical network addresses.

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