A Stratechery interview with the CEO of Tailscale dropped a few weeks ago. Tailscale is one of my favourite kinds of companies — focused on a single product that’s deeply technical and yet simple and delightful to use. I’m a longtime user and love the product. The interview is fun to listen to.
It reminded me of this old article that Tailscale published: How NAT traversal works. It’s an in-depth treatise on a topic that most of us never think about, but a critical problem to solve for those designing peer-to-peer networking software.
It’s a very long read, but a captivating one nevertheless. There are all kinds of interesting technical details, and some aha moments like how the ideas of The Birthday Paradox are used to devise an algorithm for NAT-busting (in a section delightfully titled “NAT notes for nerds”).