"The RADIUS (Remote Authentication Dial-In User Service)
protocol has long been a standard authentication, authorization and
accounting protocol for Internet service providers and businesses.
It determines who you are, what you're allowed to do, and records
how long you did it for. It works for more than just dialup
users--it also works for DSL, cable, and wireless users.
"Anytime you study RADIUS, you read about 'AAA,' the
authentication/authorization/accounting functions. Sometimes it is
even called RADIUS-AAA. (And now you know it's not about a
twelve-step program or automobile club.) The accounting part can be
used for billing or statistical analysis. RADIUS can use text files
of users for authentication, or hook into Linux/Unix password
files, NIS (Network Information Service), LDAP (Lightweight
Directory Access Protocol) directories, MySQL and other