This post delves into the intricate workings of NAT traversal to connect devices directly to each other, despite obstacles like stateful firewalls and NAT devices. By sharing tricks like leveraging UDP packets flow, STUN protocol for address discovery, and the role of NATs in altering packet destinations, the author breaks down complex networking concepts with clear examples and explanations. The clever coordination of processes like synchronization server and DERP servers in Tailscale showcases unique solutions to create bidirectional communication through multiple layers of firewalls and NATs. The emphasis on practical applications and scalability makes this guide an essential resource for understanding modern networking challenges.
https://tailscale.com/blog/how-nat-traversal-works