Methods and apparatus for detecting VOIP spoofing attacks in systems that provide communication services over IP networks, for gathering information that can be used for preventing or mitigating future malicious attacks, are described. The methods and apparatus send various signals and check for expected responses. Actual responses and/or lack of responses to signals, e.g., messages, are detected, logged and used for making decisions as well as generating a record for informational purposes and analysis which can facilitate identification of common features of malicious packets and/or messages. The methods are well suited for use in a session border controller.