Explore the evolution of IPsec in this invited talk by Steven Bellovin from Columbia University, delivered at the Conference for Failed Approaches and Insightful Losses in Cryptology (CFAIL 2020). Delve into the history, structure, and scenarios of IPsec, examining its headers, integrity, encryption, and authentication methods. Analyze the state of cryptography, RFC developments, and organizational politics that influenced IPsec's development. Investigate the problems faced, lessons learned, and recent changes in IPsec implementation. Engage with thought-provoking questions on standards, universal authentication methods, and the future direction of network security.