I have a FreeBSD 7.2 box as the boarder router/firewall with ipfw compiled into kernel. Also I have a server in my network which collects and graphs various monitoring information from network with MySQL, PHP and Apache installed. I would like to know if there is a tool to collect Bandwidth usage information from FreeBSD box per subnet, NOT per port, NOT per IP, just per subnet, I mean it can monitor per IP but it should graph bandwidth usage per subnet. The desirable way is to keep statistic collector on FreeBSD box send this info to MySQL and graph with PHP. But all other options can be acceptable.
Thank you in advance