Note: Many topics at this site are reduced versions of the text in "The Encyclopedia of Networking and Telecommunications." Search results will not be as extensive as a search of the book's CD-ROM.

Logon (or login) is a procedure that a user follows to gain access to a privileged system, such as a network, a file server, a database, a Web server, or some other system. Logon software usually runs when the workstation is turned on or when a user types a command such as LOGON or LOGIN. The logon procedure asks for an account name and a password. If the user enters either of these incorrectly, the logon procedure usually allows another chance for the user to log on. After a certain number of repeated failures to supply the correct logon information, the system assumes the user is an intruder and locks the account from further logon attempts.

Users typically log onto a user account and are then given access to a system. The user account may be part of a directory service such as NDS (Novell Directory Services). Accounts are created by system administrators and stored on security servers. Users may be required to log on to every system they attempt to access. Pass-through security systems or single sign-on systems allow users to log on once and carry their security credentials to other servers. Those servers trust the original logon and allow users access. These schemes are typically implemented on intranets. See "Authentication and Authorization" for a continuation of this topic.

Access to resources is based on access control lists. See "Access Control" for more information.

A user account may have various security restrictions applied to it. A supervisor may apply logon restrictions to the user account that do the following:

• Restrict the time the user can log on, thus preventing the user from logging on after hours.


• Specify the workstation where a user logs on, preventing the user from logging on at unsupervised workstations.


• Require unique passwords, thus forcing the user to create a password unlike one the user recently used.


• A logon restriction can define an expiration date for the account, locking out the user after a certain period of time.

Copyright (c) 2001 Tom Sheldon and Big Sur Multimedia.
All rights reserved under Pan American and International copyright conventions.