ntop is a network probe that shows network usage in a way similar to what top

Top (Unix)

top is a program found in many Unix-like operating systems. It produces an ordered list of running processes selected by user-specified criteria, and updates it periodically. Default ordering by CPU usage, and only the top CPU consumers shown top shows how much processing power and memory are...

does for processes

Process (computing)

In computing, a process is an instance of a computer program that is being executed. It contains the program code and its current activity. Depending on the operating system , a process may be made up of multiple threads of execution that execute instructions concurrently.A computer program is a...

. In interactive mode, it displays the network status on the user's terminal. In Web mode, it acts as a web server

Web server

Web server can refer to either the hardware or the software that helps to deliver content that can be accessed through the Internet....

, creating a HTML

HTML

HyperText Markup Language is the predominant markup language for web pages. HTML elements are the basic building-blocks of webpages....

 dump of the network status. It sports a NetFlow

Netflow

NetFlow is a network protocol developed by Cisco Systems for collecting IP traffic information. NetFlow has become an industry standard for traffic monitoring and is supported by platforms other than Cisco IOS and NXOS such as Juniper routers, Enterasys Switches, vNetworking in version 5 of...

/sFlow

SFlow

sFlow is a technology for monitoring network, wireless andhost devices.The sFlow.org consortium is the authoritative source for the sFlow protocol specifications: previous version of sFlow, including RFC 3176, have been deprecated.- Operation :...

 emitter/collector, a HTTP

Hypertext Transfer Protocol

The Hypertext Transfer Protocol is a networking protocol for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web....

-based client interface for creating ntop-centric monitoring applications, and RRD

RRDtool

RRDtool aims to handle time-series data like network bandwidth, temperatures, CPU load, etc...

 for persistently storing traffic statistics.

ntop is available for both Unix

Unix

Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...

 and Win32-based platforms. It has been developed by Luca Deri, an Italian

Italy

Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...

 research scientist and network manager at University of Pisa

University of Pisa

The University of Pisa , located in Pisa, Tuscany, is one of the oldest universities in Italy. It was formally founded on September 3, 1343 by an edict of Pope Clement VI, although there had been lectures on law in Pisa since the 11th century...

.

Common usage on a Linux

Linux

Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...

 system is to start the ntop daemon (/etc/init.d/ntopd start), then one can use the web interface to ntop via visiting http://127.0.0.1:3000 provided the loopback device has been started (/etc/init.d/net.lo start) and the listening port for ntop is 3000 (look out for the -w option in ps

Ps (Unix)

In most Unix-like operating systems, the ps program displays the currently-running processes. A related Unix utility named top provides a real-time view of the running processes....

 aux | grep

Grep

grep is a command-line text-search utility originally written for Unix. The name comes from the ed command g/re/p...

ntop).