Networking Monitoring Tools

Any idea where can I get a freware to monitor the network traffic in my department? The best is this tool can store the log files. Thanks!

See this thread (searching first will get you answers quicker)

To add to that, I have always used Trinux (trinux.sourceforge.net). It's basically all the linux network tools clumped together. It's pretty sweet and flexible. A bit of a learning curve if you aren't familiar with all the tools or linux.

Thanks to all of you for your information!

you can use ipcad - IPCAD - IP traffic accounting daemon download | SourceForge.net
this tool can sniff interface (via libpcap,bpf,ulog,libipq ) and dump statistic into dump-file or export it via rsh for billing systems (for example www.netup.biz).
Or you can use - fprobe download | SourceForge.net. This tool do the same as ipcad but export via netflow (cisco's protocol).

OK! You can use software iptraf. This is small tools to view status of network and more:

iptraf.seul.org