5.1 Introduction to FreeRADIUS

The developers of FreeRADIUS speak on their product and its development, from the FreeRADIUS web site:

FreeRADIUS is one of the most modular and featureful [sic] RADIUS servers available today. It has been written by a team of developers who have more than a decade of collective experience in implementing and deploying RADIUS software, in software engineering, and in Unix package management. The product is the result of synergy between many of the best-known names in free software-based RADIUS implementations , including several developers of the Debian GNU/Linux operating system, and is distributed under the GNU GPL (version 2).

FreeRADIUS is a complete rewrite, ground-up compilation of a RADIUS server. The configuration files exhibit many similarities to the old Livingston RADIUS server. The product includes support for:

• Limiting the maximum number of simultaneous logons , even on a per- user basis

• More than one DEFAULT entry, with each being capable of "falling through" to the next

• Permitting and denying access to users based on the huntgroup to which they are connected

• Setting certain parameters to be huntgroup specific

• Intelligent "hints" files that select authentication protocols based on the syntax of the username

• Executing external programs upon successful login

• Using the $INCLUDE filename format with configuration, users, and dictionary files

• Vendor-specific attributes

• Acting as a proxy RADIUS server

FreeRADIUS supports the following popular NAS equipment:

• 3Com/USR Hiper Arc Total Control

• 3Com/USR NetServer

• 3Com/USR TotalControl

• Ascend Max 4000 family

• Cisco Access Server family

• Cistron PortSlave

• Computone PowerRack

• Cyclades PathRAS

• Livingston PortMaster

• Multitech CommPlete Server

• Patton 2800 family

FreeRADIUS is available for a wide range of platforms, including Linux, FreeBSD, OpenBSD, OSF/Unix, and Solaris. For the purposes of this book, I will focus on FreeRADIUS running under Linux. Also, as of this printing, a stable Version 1.0 of the product had not been released. However, development of the server is very stable, careful, and somewhat slow, so changes to the procedures mentioned are unlikely . In the event a procedure does change, it's likely to be a relatively small modification. Always check the FreeRADIUS web site for up-to-date details.