ntop (short from network top) is an open source and completely free command-line software that gives users detailed information about their network traffic, using the rrdtool and libpcap packages, under GNU/Linux and UNIX-like operating systems.
Features at a glance
The program is capable of sorting network traffic based on protocols. It displays network traffic and traffic statistics, stores traffic statistics in RRD (Round-Robin Database) format, and identifies computer users and host operating systems.
In addition, the software can be used to display IP traffic distribution, analyze IP traffic, display IP traffic subnet matrix, report IP protocol usage, as well as to output RMON-like network traffic statistics.
Can act as a NetFlow and sFlow collector
The ntop software is also capable of acting as a NetFlow or sFlow collector for different flows generated by switches like Foundry Networks, or various routers, such as the ones manufactured by Cisco and Juniper.
Like any other command-line software, ntop comes with various command-line options, which can be viewed at a glance along with the usage message by running the ‘ntop --help’ command in a console environment, such as a terminal emulator.
Please keep in mind that before running the daemon script for the first time, you need to run ntop as root (system administrator) in order to set an administrator password, otherwise the program will give you errors and won't work.
Getting started with ntop
To use ntop on your GNU/Linux operating system, you will need to install the runtime dependencies listed in the first paragraph, as well as to download the latest release of the software from Softpedia or from its website.
Save the package on your Home directory and unpack it. Open a Terminal app, go to the location where you’ve extracted the archive file (e.g. cd /home/softpedia/ntop-5.0.1) and run the ‘sh autogen.sh’ command.
Then, run the ‘./configure && make’ command to configure/optimize and compile the program, followed by the ‘sudo make install’ command to install ntop system wide and make it available to all users on your machine.