Scapy is a powerful interactive packet
manipulation tool, packet generator, network
scanner, network discovery tool, and packet
sniffer. It provides classes to interactively
create packets or sets of packets, manipulate
them, send them over the wire, sniff other packets
from the wire, match answers and replies, and
more. Interaction is provided by the Python
interpreter, so Python programming structures can be used (such as variables, loops, and functions). Report modules are possible and easy to make. It is intended to do about the same things as ttlscan, nmap, hping, queso, p0f, xprobe, arping, arp-sk, arpspoof, firewalk, irpas, tethereal, tcpdump, etc.