In the context of network security, a spoofing attack is a condition in which one person or a program successfully masquerades as another. This is done by providing counterfeit data with the malicious intention of gaining an illegitimate advantage. Spoofing attack which may be generated in various layer of Open Systems Interconnection model (OSI model) is discussed in this chapter. The chapter ends with discussing about the possible spoofing attacks in network layer and the relevant defense mechanism of the same. The detailed analysis and discussion is made on the spoofing attack over the Network layer because, Denial-of-Service (DoS) and Distributed Denial-of-Service (DDoS) attacks more devastating while using network protocol like Internet Protocol (IP) which have become more of a threat than ever for the past few years.
