Facebook runs a global infrastructure that supports thousands of services, with many new ones spinning up daily. Protecting network traffic is taken very seriously, and engineers must have a sustainable way to enforce security policies transparently and globally. One requirement is that all traffic that crosses “unsafe” network links must be encrypted with TLS 1.2 or above using secure modern ciphers and robust key management. Mingtao and Ajanthan describe the infrastructure they built for enforcing the “encrypt all’ policy on the end hosts, as well as alternatives and trade-offs encompassing how they use BPF programs. Additionally, they discuss Transparent TLS (TTLS), a solution that they’ve built for services that could not enable TLS natively or could not easily upgrade to a newer version of TLS.