How NAT broke the open Internet and made peer-to-peer a pipe dream
Internet centralization and the original sin of NAT
Network Address Translation (NAT) was introduced in 1994 as a short-term fix for IPv4 address exhaustion, but it has had a lasting, corrosive effect on the Internet's architecture. By hiding devices behind a single public IP, NAT made it nearly impossible to host services from home, forcing a reliance on port forwarding, UPnP, STUN, TURN, and ICE—none of which fully restore true peer-to-peer connectivity. Even IPv6, the supposed long-term solution, is often undermined by ISPs that continue to apply NAT-like restrictions. This post argues that NAT is the original sin of Internet centralization, normalizing a client-server model and making self-hosting difficult, which has contributed to the rise of walled gardens.
NAT certainly isn’t the only reason why the modern internet is full of centralized walled gardens, but it was the first — it’s why it’s hard to send a file to someone, it’s why you don’t run your email on your own computer, and why running your own services at all is difficult and often expensive.