This is a relatively simple port of OpenRADIUS. From the faq...

------------------------------
What is OpenRADIUS?

OpenRADIUS is a piece of software that links your network access
devices to your user-, service profile-, and usage databases.

As such, OpenRADIUS isn't unique; other servers that speak the
RADIUS protocol do the same. But it is unique in the flexibility
it offers you in building this link, because it puts you in full
control of the business rules used inside the server and the ways
it talks to your databases - without anybody having to hack the
source code.
------------------------------

WWW: http://www.openradius.net/