A Linux or UNIX server can use MRTG graphs to display bandwidth usage. MRTG (Multi Router Traffic Grapher) is a free software for monitoring the traffic load on network links. It allows the user to see traffic load on a network over time in graphical form. See how to setup and use MRTG for more info:
- MRTG displays graphs for 24 hrs, weekly, monthly and previous month usage. In most cases your IDC should provide the same. If not you can install MRTG on your own server by following these instructions.
- Centos Install and Configure MRTG
- You can also use a tool called vnstat a console-based network traffic monitor. It keeps a log of hourly, daily and monthly network traffic for the selected interface(s). However, it isn’t a packet sniffer.