netsniff-ng

netsniff-ng is a free Linux network analyzer and networking toolkit originally written by Daniel Borkmann. Its gain of performance is reached by zero-copy mechanisms for network packets (RX_RING, TX_RING),^[4] so that the Linux kernel does not need to copy packets from kernel space to user space via system calls such as recvmsg().^[5] libpcap, starting with release 1.0.0, also supports the zero-copy mechanism on Linux for capturing (RX_RING), so programs using libpcap also use that mechanism on Linux.

netsniff-ng toolkit

Original author(s)	Daniel Borkmann
Developer(s)	Daniel Borkmann, Tobias Klauser, Herbert Haas, Emmanuel Roullit, Markus Amend and many others
Initial release	December, 2009
Stable release	0.6.8^[1] / 11 January 2021; 2 years ago (11 January 2021)
Repository	https://github.com/netsniff-ng/netsniff-ng
Written in	C
Operating system	Linux
Available in	English
Type	Network management Network engineering Computer security
License	GPLv2^[2]
Website	http://netsniff-ng.org^[3]

Overview

netsniff-ng was initially created as a network sniffer with support of the Linux kernel packet-mmap interface for network packets, but later on, more tools have been added to make it a useful toolkit such as the iproute2 suite, for instance. Through the kernel's zero-copy interface, efficient packet processing can be reached even on commodity hardware. For instance, Gigabit Ethernet wire-speed has been reached with netsniff-ng's trafgen.^[6][7] The netsniff-ng toolkit does not depend on the libpcap library. Moreover, no special operating system patches are needed to run the toolkit. netsniff-ng is free software and has been released under the terms of the GNU General Public License version 2.

The toolkit currently consists of a network analyzer, packet capturer and replayer, a wire-rate traffic generator, an encrypted multiuser IP tunnel, a Berkeley Packet Filter compiler, networking statistic tools, an autonomous system trace route and more:^[8]

• netsniff-ng, a zero-copy analyzer, packet capturer and replayer, itself supporting the pcap file format
• trafgen, a zero-copy wire-rate traffic generator
• mausezahn, a packet generator and analyzer for HW/SW appliances with a Cisco-CLI
• bpfc, a Berkeley Packet Filter compiler
• ifpps, a top-like kernel networking statistics tool
• flowtop, a top-like netfilter connection tracking tool with Geo-IP information
• curvetun, a lightweight multiuser IP tunnel based on elliptic-curve cryptography
• astraceroute, an autonomous system trace route utility with Geo-IP information

Distribution specific packages are available for all major operating system distributions such as Debian^[9] or Fedora Linux. It has also been added to Xplico's Network Forensic Toolkit,^[10] GRML Linux, SecurityOnion,^[11] and to the Network Security Toolkit.^[12] The netsniff-ng toolkit is also used in academia.^[13][14]

Basic commands working in netsniff-ng

In these examples, it is assumed that eth0 is the used network interface. Programs in the netsniff-ng suite accept long options, e.g., --in ( -i ), --out ( -o ), --dev ( -d ).

• For geographical AS TCP SYN probe trace route to a website:

astraceroute -d eth0 -N -S -H <host e.g., netsniff-ng.org> 

• For kernel networking statistics within promiscuous mode:

ifpps -d eth0 -p 

• For high-speed network packet traffic generation, trafgen.txf is the packet configuration:

trafgen -d eth0 -c trafgen.txf 

• For compiling a Berkeley Packet Filter fubar.bpf:

bpfc fubar.bpf 

• For live-tracking of current TCP connections (including protocol, application name, city and country of source and destination):

flowtop 

• For efficiently dumping network traffic in a pcap file:

netsniff-ng -i eth0 -o dump.pcap -s -b 0 

Platforms

The netsniff-ng toolkit currently runs only on Linux systems. Its developers decline a port to Microsoft Windows.^[15]

See also

• Comparison of packet analyzers
• OpenVPN
• Packet generator
• Tcpdump
• Traceroute
• Traffic generation model
• Wireshark
• Xplico

References

1. "Release 0.6.8". 11 January 2021. Retrieved 13 January 2021.
2. "netsniff-ng license". GitHub. Retrieved 20 December 2021.
3. Error: Unable to display the reference properly. See the documentation for details.
4. "Description of the Linux packet-mmap mechanism". Retrieved 6 November 2011.
5. "netsniff-ng homepage, abstract, zero-copy". from the original on 8 September 2016. Retrieved 6 November 2011.
6. "Network Security Toolkit Article about trafgen's performance capabilities". Retrieved 6 November 2011.
7. . 16 October 2011. Archived from the original on 25 April 2012. Retrieved 6 November 2011.
8. "netsniff-ng README". GitHub. Retrieved 16 February 2018.
9. "netsnif-ng in Debian".
10. "Xplico support of netsniff-ng". Retrieved 6 November 2011.
11. "Security Onion 12.04 RC1 available now!". Retrieved 16 December 2012.
12. "Network Security Toolkit adds netsniff-ng". Retrieved 6 November 2011.
13. . Archived from the original on 10 November 2011. Retrieved 7 November 2011.
14. "netsniff-ng's trafgen at Columbia University". Retrieved 7 November 2011.
15. "netsniff-ng FAQ declining a port to Microsoft Windows". Retrieved 21 June 2015.

External links

• Official netsniff-ng website
• netsniff-ng FAQ
• netsniff-ng at GitHub
• Linux' packet mmap(), BPF, and the netsniff-ng toolkit, talk at DevConf (long)
• , talk at OpenSourceDays (short)
• netsniff-ng(8) – Linux Administration and Privileged Commands Manual