IP spoofing is an attempt to masquerade as a trusted correspondent, so it is an ideal strategy to use in a man-in-the-middle attack. In a MitM attack, a hacker intercepts a communication, usually posing as the server. The interception system spoofs the address of the server, fooling the client. In some instances, the MitM attack might also have to pose as the client in communications with the server to obtain the convincing output to return to the client.