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ntop is a network traffic probe that shows the network usage, similar to what the popular top Unix command does. ntop is based on libpcap and it has been written in a portable way in order to virtually run on every Unix platform and on Win32 as well.

ntop users can use a a web browser to navigate through ntop (that acts as a web server) traffic information and get a dump of the network status 1.

What ntop can do for me?

  • Sort network traffic according to many protocols
  • Show network traffic sorted according to various criteria
  • Display traffic statistics
  • Store on disk persistent traffic statistics in RRD format
  • Identify the indentity (e.g. email address) of computer users
  • Passively (i.e. without sending probe packets) identify the host OS
  • Show IP traffic distribution among the various protocols
  • Analyse IP traffic and sort it according to the source/destination
  • Display IP Traffic Subnet matrix (who’s talking to who?)
  • Report IP protocol usage sorted by protocol type
  • Act as a NetFlow/sFlowcollector for flows generated by routers (e.g. Cisco and Juniper) or switches (e.g. Foundry Networks)
  • Produce RMON-like network traffic statistics


  • Unix (including Linux, *BSD, Solaris, and MacOSX)
  • Win32 (Win95 and above including Vista


  • Loopback
  • Ethernet (including 802.11Q)
  • Token Ring
  • Raw IP
  • FDDI
  • FibreChannel
  • ...and many more


Memory Usage

  • It depends on the ntop configuration, number of hosts, and number of active TCP sessions. In general it ranges from a few MB (little LAN) to 100 MB for a WAN.

CPU Usage

  • It depends on the ntop configuration, and traffic conditions. On a modern PC and large LAN, it is less than 10% of overall CPU load.


  • IPv4/IPv6
  • IPX
  • DecNet
  • AppleTalk
  • Netbios
  • OSI
  • DLC
  • …and many more

IP Protocols

  • Fully User Configurable

Additional Features

  • VoIP support (SIP, Cisco SCCP and Asterisk IAX)
  • NetFlow (including v5 and v9) and IPFIX support
  • Network Flows
  • Local Traffic Analysis
  • Multithread and MP (MultiProcessor) support on both Unix and Win32
  • Python lightweight API for extending ntop via scripts
  • Support of both NetFlow andsFlowas flow collector. ntop can collect simultaneously from multiple probes.
  • Traffic statistics are saved into RRDdatabases for long-run traffic analysis.
  • Internet Domain, AS (Autonomous Systems), VLAN (Virtual LAN) Statistics
  • Network assets discovery and categorization according to their OS and users
  • Protocol decoders for many internet protocols
  • Advanced ‘per user’ HTTP password protection with encrypted passwords
  • RRDsupport for persistently storing per-host traffic information
  • Passive remote host fingerprint (Courtesy of ettercap)
  • HTTPS (Secure HTTP via OpenSSL)
  • Virtual/multiple network interfaces support
  • Graphical ntop launcher (Win32 only)