Winners of the Cisco VIRL Giveaway 2016 are in! Scroll down for the announcement


Ostinato is a packet crafter, network traffic generator and analyzer with a friendly GUI and powerful Python API for network test automation. Craft and send packets of several streams with different protocols at different rates. It is “Wireshark in Reverse”.

Ostinato aims to provide a traffic generator and network tester tool for every network engineer and developer - something not possible today with existing commercial network test equipment. With the right tool, network developers and engineers can do their jobs better and improve the quality of networking products.


  • FLOSS - Free, Libre, Open-Source Software
  • Cross-Platform - runs on Windows, Linux, BSD and Mac OS X
  • Useful for both network load testing and functional testing
  • Use via GUI or Python API
  • Support for the most common standard protocols
    • Ethernet/802.3/LLC SNAP
    • VLAN (with QinQ)
    • ARP, IPv4, IPv6, IP-in-IP a.k.a IP Tunnelling (6over4, 4over6, 4over4, 6over6)
    • Any text based protocol (HTTP, SIP, RTSP, NNTP etc.)
    • More protocols in the works …
  • Set a value for any field of any protocol
  • Vary packet fields across packets at run time e.g. changing IP/MAC addresses
  • User provided Hex Dump - specify some or all bytes in a packet
  • User defined script to substitute for an unimplemented protocol (EXPERIMENTAL)
  • Stack protocols in any arbitrary order
  • Create and configure multiple streams
  • Configure stream rates, bursts, no. of packets
  • One agent can control and configure multiple ports on multiple computers generating traffic
  • Multiple agents can share control over a single port on a single computer
  • Exclusive control of a port to prevent the OS from sending stray packets provides a controlled testing environment (Windows only)
  • Statistics Window shows port receive/transmit statistics and rates for realtime network monitoring and measurement
  • Capture network traffic (needs Wireshark to view the captured packets)
  • Open and edit PCAP files, replay and save back
  • Framework to add new protocol builders easily
  • Network Device Emulation (ARP and ICMP) for multiple IP hosts to aid in network traffic simulation


Ostinato is licensed under GNU GPLv3

Giveaway - free VIRL

And the winners of the Cisco VIRL Licenses Giveaway 2016 are -

a Rafflecopter giveaway

See VIRL Giveaway 2015 Winners

Thanks to Cisco VIRL for the licenses and Rafflecopter for the giveaway infrastructure.




October 2016

  • Winners of the VIRL Giveaway 2016 announced - Shane S and Sooraj T

June 2016

March 2016

See All News


…thanks for developing ostinato: this was a really missing piece in the open-source networking world - Luca Deri ( [Email]

Before I go any further I need to give another shout out to an excellent open source piece of software I found. Ostinato turns you into a packet ninja. There’s literally no limit to what you can do with it. Without Ostinato I could have never gotten beyond this point - Kristian Kielhofner (“Packets of Death” AstLinux, Star2Star) [Blog]

Napatech supports a number of open-source software applications that can also help customers accelerate their development … Ostinato for Traffic Generation [Press Release]

Ostinato is more stable [than similar tools] and has a more complete roadmap [Blog]

Mailing List

For queries/bugs/feedback/suggestions, send an email to the mailing list -

You can also join the mailing list or read the archives