HP-UX AAA Server A.08.00.01 Administrator's Guide

26 Customizing the HP-UX AAA Server Using the Finite
State Machine
The main component of the server’s software engine is the Finite State Machine (FSM)
and a few associated routines. At server startup, the FSM reads instructions from a
state table by loading and parsing a .fsm file. By default, it loads the radius.fsm
file, unless it is missing or if you have specified another .fsm file using the radiusd
-f command. The .fsm file defines a state table that includes the states, events, and
actions that determine how a request is processed.
You can track different versions of state tables by adding the following line to the .fsm
file:
%FSMID Version-String
Version-String
is the version information. This string will appear in radcheck
output.
States
In the Finite State Machine, a request will transition through a series of states, beginning
with a state that includes possible starting events. The action specified to be called first
in response to an initial authentication request will return a value, an event that
determines the next state to transition to. Within each state, the next action is triggered
by an event (based on previous state and action and a value, typically ACK or NAK,
returned by the previous action), which in turn directs the flow of the request to another
state, until an End state is reached. Figure 26-1 shows at a high level the process that
occurs, as the result of a request, in the finite state machine.
390 Customizing the HP-UX AAA Server Using the Finite State Machine