Linux LDAP authentication (Linux.com)
When you have to administer a network of many machines, you quickly find out how much duplication of effort is involved with normal administrative tasks. Routine operations like changing passwords, canceling accounts, and modifying groups become time-consuming if repeated on many individual machines. Centralizing user and authentication information can solve these issues. The former king of centralized authentication systems was NIS, or Network Information System. NIS is a simple and well-supported technology, but it's also insecure. LDAP, short for Lightweight Directory Access Protocol, is now the preferred way of managing centralized user accounts."