Platform-Specific information about adding packet capture support
You will need to make sure the machine on which you're running is configured to support packet capture, e.g. you might need a capture driver installed. The way this is done differs from operating system to operating system.
On Linux, you need to have "packet socket" support enabled in your kernel. Your distribution might enable this by default in the kernel; most recent versions of distributions do so. If it does not, see the "Packet socket" item in the Linux "Configure.help" file.
BSD (including Mac OS X)
On various BSDs, you need to have BPF support enabled in your kernel. In Mac OS X, and in newer versions of at least some free-software BSDs, it's enabled by default. In other BSDs, see the documentation for your system for information on how to enable BPF support.
In SunOS 3.x, 4.x, and 5.x, packet capture support is present by default.
In HP-UX 9.x, 10,x, and 11.x, packet capture support is present by default. (XXX - true of 9.x?)
On DEC OSF/1, Digital UNIX, or Tru64 UNIX, you need to have packet filtering support in your kernel; the doconfig command will allow you to configure and build a new kernel with that option.
On Irix, packet capture support is present by default.
On Windows, you need to have WinPcap installed in order to capture network traffic.