Understanding the network.pdf - Back to Home

makes it easier to configure, because the server only needs to know
about one interface.
Setting Up RADIUS
RADIUS is a client/server communications protocol used in
authentication and accounting. Clients (routers, access servers, and
so on) forward user connection information to the RADIUS server,
where the user's access is verified. User information or profiles are
stored on the RADIUS server as a collection of attribute-value pairs
that describe the user's access privileges. These attribute-values are
in part defined as part of the RADIUS protocol. There are about 50
standard attributes, plus an innumerable amount of vendor-specific
attributes.
If you are planning to use a free RADIUS version, you will be running
it on UNIX. The best source for the code is at Merit. Many UNIX
implementations come with prebuilt RADIUS implementations that
are just fine. However, you cannot adjust how the daemon behaves if
you do not have the source code, and RADIUS does support some
different compiling options. Depending on the version of RADIUS you
have, the binary will be located in /etc/raddb/radiusd or
/usr/private/etc/radiusd. If the binary code is not in either of
these places, you can use the UNIX command to find it. The
directory where RADIUS looks for its configuration files is built into the
daemon. The default (again it depends on the version) is /etc/raddb
or /usr/private/etc/raddb. The default can be changed using a
flag when you start the RADIUS daemon, which is usually part of the
system's startup scripts.
To start RADIUS from /etc/rc.local, use
if [ -f /etc/raddb/users -a -f /usr private/etc/users ]; then
echo -n 'radiusd'; radiusd
fi
RADIUS stores its logfile in its home directory, etc/raddb.
Accounting files are stored in /var/account/radius. This, like its
home directory, can be changed in the source code or with a flag.