Pig or (Packet intruder generator) is a Linux based packet crafting tool. You can use Pig for a number of different purposes such as testing your IDS/IPS through to spoofing ARP. Pig brings with it a number of well-known attack signatures which are ready to be used and you can expand upon these should you need something more specific to meet your requirements. It is only possible to create IPv4 signatures within the transport layer based on TCP, UDP and ICMP. You can also create signatures based on the ARP protocol. Pigsty files are plain text files where you can define a set of packet signatures.