The IPID is the Identification field of the IP protocol packet header which a;long
with the source address uniquely identifies the packet. The IPID is used to reassemble
the packet should it be fragmented. Every fragement of the packet will then have
the same IPID for the destination device identify them all to be a simgle packet.
The IPID is primarily used in the Idle Port Scanning by a hacker where he spoofs
a victims IP address to then use it to scan a target network or system. Various
Operating Systems generate these IPIDs in different ways.