System for Internet-Level Knowledge (SiLK) project is a collection of traffic analysis tools.
gulog is a GTK UUCP log and traffic monitor.
ipaudit-web logs network activity, maintains traffic summaries, and presents Web-accessible graphs and reports.
The MZL & Novatech TrafficStatistic Linux Server collects IP usage statistics from the network interfaces.
Netacct-mysql is modified version of traffic accounting daemon net-acct which stores collected data in MySQL.
Traff sniffs your network interfaces and accounts the IP traffic on an IP basis.