Learn in the textbookAttacks on Networks and Communication Paths
DefinitionIP spoofing (IPスプーフィング) is a technique that forges the source IP address (IPアドレス) of the packets (パケット, the small units data is split into for sending) so they look as if they came from another device.
ExplanationEach packet carries a source IP address alongside its destination, and the receiving device normally trusts that value to decide who sent it. Because the sender can rewrite the source value, a system that permits traffic on IP address alone can be breached by packets posing as an approved device, and the countermeasure is authentication that does not depend only on the IP address. The technique is also used to hide where an attack comes from.
AnalogyIt is like writing a trusted business partner's address in the return-address corner of an envelope. If the recipient opens it based on the return address alone, they are fooled.
Memory hookThe English word "spoof" means to trick someone or to mimic something in fun.