| Developer(s) | The Tcpdump team |
|---|---|
| Stable release | 1.2.0 / July 24, 2011 |
| Operating system | Linux, Solaris, FreeBSD, NetBSD, OpenBSD, Mac OS X, additional *NIX systems |
| Type | Library for packet capture |
| License | BSD license |
| Website | www.tcpdump.org |
| Developer(s) | Riverbed Technology |
|---|---|
| Stable release | 4.1.2 / July 2, 2010[1] |
| Operating system | Microsoft Windows |
| Type | Library for packet capture |
| License | Freeware |
| Website | www.winpcap.org |
In the field of computer network administration, pcap (packet capture) consists of an application programming interface (API) for capturing network traffic. Unix-like systems implement pcap in the libpcap library; Windows uses a port of libpcap known as WinPcap.
Monitoring software may use libpcap and/or WinPcap to capture packets travelling over a network and, in newer versions, to transmit packets on a network at the link layer, as well as to get a list of network interfaces for possible use with libpcap or WinPcap.
The implementers of the pcap API wrote it in C, so other languages such as Java, .NET languages, and scripting languages generally use a wrapper; no such wrappers are provided by libpcap or WinPcap itself. C++ programs may link directly to the C API or use an object-oriented wrapper.
Contents |
libpcap and WinPcap provide the packet-capture and filtering engines of many open source and commercial network tools, including protocol analyzers (packet sniffers), network monitors, network intrusion detection systems, traffic-generators and network-testers.
libpcap and WinPcap also support saving captured packets to a file, and reading files containing saved packets; applications can be written, using libpcap or WinPcap, to be able to capture network traffic and analyze it, or to read a saved capture and analyze it, using the same analysis code. A capture file saved in the format that libpcap and WinPcap use can be read by applications that understand that format, such as tcpdump, Wireshark, CA NetMaster, or Microsoft Network Monitor 3.x.
The MIME type for the file format created and read by libpcap and WinPcap is application/vnd.tcpdump.pcap. The typical file extension is .pcap, although .cap and .dmp are also in common use.[2]
libpcap was originally developed by the tcpdump developers in the Network Research Group at Lawrence Berkeley Laboratory. The low-level packet capture, capture file reading, and capture file writing code of tcpdump was extracted and made into a library, with which tcpdump was linked. It is now developed by the same tcpdump.org group that develops tcpdump.
WinPcap consists of:
Programmers at the Politecnico di Torino wrote the original code; as of 2008 CACE Technologies, a company set up by some of the WinPcap developers, develops and maintains the product. CACE Technologies was acquired by Riverbed Technology on October 21, 2010[3]
There are at least four alternative Python extensions offering a Python interface to the pcap library:
There is also a Python extension that includes its own code to read and write pcap files without using the pcap library: