darkstat

Captures network traffic, calculates statistics about usage, and serves reports over HTTP.

Features:

Traffic graphs, reports per host, shows ports for each host.
Embedded web-server with deflate compression.
Asynchronous reverse DNS resolution using a child process.
Small. Portable. Single-threaded. Efficient.
Supports IPv6.

Screenshots: (click)

Code:

Releases
GitHub
ChangeLog

Quickstart:

# ./configure
# make

Once built, this is all it takes to get darkstat running:

# darkstat -i eth0

Although it's possible to configure / complicate things further, once out of the box, darkstat will just work without much trouble on your part.

Slower start:

Portability:

darkstat should build and run on any modern UNIX system that has libpcap. It has been reported to build on:

Efficiency:

On my FreeBSD router, ppp takes an order of magnitude more CPU time than darkstat. If your system can keep up with PPPoE, you should have no trouble running darkstat.