Pcapy is a Python extension module that interfaces with the libpcap packet capture library. Pcapy enables python scripts to capture packets on the network. Pcapy is highly effective when used in conjunction with a packet-handling package such as Impacket, which is a collection of Python classes for constructing and dissecting network packets.

Advantages of Pcapy

• Works with Python threads.
• Functions in both UNIX with libpcap and Windows with WinPcap.
• Provides a simpler Object Oriented API.

Requirements

• A Python interpreter. Versions 2.1.3 and higher.
• A C++ compiler. GCC G++ 2.95, as well as Microsoft Visual Studio 6.0 or MSVC 2003 depending on the Python version.
• A Libpcap 0.9.3 or newer. Windows users should have installed WinPcap 4.0 or newer.

Download Pcapy here:

Source code

Latest stable release (0.10.5) – gzip’d tarball or zip file

Win32 binaries – Pick the appropriate Python or WinPcap version.

Latest release (0.10.5) – Windows installer – Python 2.5 and WinPcap 4.0.
0.10.4 – Windows installer – Python 2.4 and WinPcap 3.1.

Or read more here and the documentation is here.