First step:
You need to download and install the latest version of FreeRaduis [http://www.freeradius.org]

server$ tar zxvf freeradius-1.0.1.tar.gz  
server$ ./configure --prefix=/usr/local/radiusd/
server$ make

(here you need to become superuser root)

server# make install

If you don't see any errors - congratulations you have successfully installed radius server:

Next step is to configure radius server:

server# vi /usr/local/radiusd/etc/raddb/users

DEFAULT Auth-Type = Accept
  Exec-Program-Wait = "/usr/abills/libexec/rauth.pl"

server# vi /usr/local/radiusd/etc/raddb/acct_users 

DEFAULT Acct-Status-Type == Start
   Exec-Program = "/usr/abills/libexec/racct.pl"
DEFAULT Acct-Status-Type == Alive
   Exec-Program = "/usr/abills/libexec/racct.pl"
DEFAULT Acct-Status-Type == Stop
   Exec-Program = "/usr/abills/libexec/racct.pl"

 server# vi /usr/local/radiusd/etc/raddb/clients.conf

Put the IP or the name of your NAS server:

client nashost.nasdomain {
   secret = radsecret
   shortname = shorrname
}

server# vi /usr/local/radiusd/etc/raddb/radiusd.conf

The following lines have to be commented:

authorize {
  preprocess
# chap
# counter
# attr_filter
# eap
  suffix
  files
# etc_smbpasswd
# sql
# mschap
}

Download the tarball from [http://www.mysql.com]

 server$ tar xvfz mysql-4.0.23a.tar.gz
 server$ cd mysql-4.0.23a
 server$ ./configure
 server$ make
 server# make install

Create user and database:

use mysql; INSERT INTO user (Host, User, Password) VALUES ('%','abills', password('sqlpassword')); INSERT INTO db (Host, Db, User, Select_priv, Insert_priv, Update_priv, Delete_priv, Create_priv, Drop_priv, Index_priv, Alter_priv) VALUES ('localhost', 'abills', 'abills', 'Y', 'Y', 'Y', 'Y', 'Y', 'Y', 'Y', 'Y');
CREATE DATABASE abills;

server# mysqladmin flush-privileges;

Create tables in the database:

server# mysql -D abills < abills.sql

In our case using Apache and must edit httpd.conf:

Alias /billing "/usr/abills/cgi-bin/"
<Directory "/usr/abills/cgi-bin">
   <IfModule mod_rewrite.c>
      RewriteEngine on
      RewriteCond %{HTTP:Authorization} ^(.*)
      RewriteRule ^(.*) - [E=HTTP_CGI_AUTHORIZATION:%1]
      Options Indexes ExecCGI SymLinksIfOwnerMatch
   </IfModule>
   Options Indexes ExecCGI FollowSymLinks
   AllowOverride none
   DirectoryIndex users.cgi
   AddHandler cgi-script .cgi
   Order allow,deny
   Allow from all
</Directory>

<Directory "/usr/abills/cgi-bin/admin">
  Options Indexes ExecCGI SymLinksIfOwnerMatch
  AllowOverride none
  DirectoryIndex users.cgi
  order deny,allow
  deny from all
  AuthType Basic
  AuthName "ABillS"
  AuthUserFile /usr/abills/cgi-bin/admin/admins
  Satisfy Any
  require valid-user
</Directory>

You need install some perl modules before proceed:

Download it from [http://www.cpan.org]

Download it from [http://sourceforge.net/projects/abills/]

 server$ tar zxvf abills-0.24b.tgz
 server# cp -Rf abills /usr/

 server# vi /usr/abills/libexec/config.pl

 #DB configuration 
 $conf{dbhost}='localhost';
 $conf{dbname}='abills'; 
 $conf{dblogin}='abills';
 $conf{dbpasswd}='sqlpassword'; 
 $conf{ADMIN_MAIL}='info@your.domain'; 
 $conf{USERS_MAIL_DOMAIN}="your.domain";
 $conf{secretkey}="test12345678901234567890";

 server# vi /usr/abills/cgi-bin/admin/Abwconf.pm

 $dbhost='localhost';
 $dbname='abills';
 $dbuser='abills';
 $dbpasswd='sqlpassword';
 $mail_domain='your.domain';
 $mail_from='abills@your.domain';

 server# vi /etc/crontab
 \*/5  *      *    *     *   root   /usr/abills/libexec/billd -all
 1     0      *    *     *   root    /usr/abills/libexec/periodic daily
 1     0      1    *     *   root    /usr/abills/libexec/periodic monthly

Change the permissions:

server# chown -Rf www /usr/abills/cgi-bin

File /usr/abills/cgi-bin/admin/admins contain admin's password:

server# htpasswd -c /usr/abills/cgi-bin/admin/admins admin

Go to web your interface http://your.host/billing/admin/
First of all must fill the parameters for NAS server:
Going to menu:
Other→NAS configuration

Create tariff plans:
Menu:
Tarif Plans

Register a customer:
Users→Add

Testing

server# radtest testuser testpassword 127.0.0.1:1812 0 radsecret 0 127.0.0.1

See '/usr/abills/var/log/abills.log' for more details (errors,messages)

2005-08-03 12:55:55 LOG_INFO: AUTH [testuser] NAS: 1 (xxx.xxx.xxx.xxx) GT: 0.03799