NetBilling traffic acounting and billing system's principal purpose is registration and rate-based accounting of IP-traffic from and to LAN users (clients in NetBilling terms) accessing Internet from behind a PC-based router/firewall. NetBilling contains MySQL-based database for storing clients' properties and their traffic amounts in pre-defined traffic zones. These traffic zones are the sets of subnetworks' addresses and server ports which are the destination of clients' requests.

Other NetBilling features includes:

• storing of clients' monthly traffic in appropiate zones for years without any performance hit
• sending clients daily and monthly traffic reports
• payment cards genereation, which could be selled to clients to simplify depositing with their accounts
• automatic monthly fee charging
• working with negative balance for specified clients only
• personal client's dicaount (specified individually)
• clients' personal page with traffic summary, payment cards and access activation and deactivatin
• charging clients against their accounts for different services
• getting traffic summary for specified month

NetBilling has straightforward architecture based on the following components:

• open-source traffic collecting deamon net-acct
• open-source database management system MySQL
• set of Perl-scripts composing Web-interface for administrator
• client's personal Web-page (Perl script) containing traffic statistics, payment cards activator and access management
• set of Perl-scripts and shell-scripts for net-acct (trafd for FreeBSD) data analysis and traffic accounting, monthly fee collecting, reports sending and access control