This question originally appeared on Quora: Why is VPN not illegal?
Answer by Stan Hanks, pushing bits down wires since '80, on Quora
IP VPNs are mostly based on GRE which I developed starting in 1992, and which was codified into RFC-1701 and RFC-1702 thanks in large part to Tony Li in 1994. GRE was really the IP version of VPNs found in X.25 and Frame Relay networks previously.
As long as there have been packet switched networks, people have wanted to say "OK, this is all nice, but what I really want is about X bandwidth between Point A and Point Z, all the time, that I can treat as if it were real point-to-point link". In X.25, Frame Relay and ATM, these were called permanent virtual circuits.
I started building VPNs out of necessity in the mid-80s - I needed a permanent "link" to CMU and later to Purdue for some research work, the grant for which wouldn't support funding a true private line. So I, ah, "got creative" and wrote code that piggy-backed on the then-new Domain Name System, turning the unused portion of the MTU buffer into my own private channel, for which I wrote psuedo-drivers, then opened a new "network link" between the two sites. Poof. New link, doesn't show up on the ARPAnet routing topology and best of all didn't come out of my budget...
Fast forward to today.
If I could do that then, with VAX CPU performance barely on par with the Atom chip running my refrigerator, and more memory in my iPhone than in the whole ARPAnet then, what's to stop anyone, really, from doing that or more today?
You can legislatively disallow it. You can't enforce against it.
Want to block GRE? Sure, knock yourself out. I'll tunnel through HTTP Port 80, which you dare not block because to 99.9% of the world, that IS "the Internet"...
Throw some DPI at me to catch "bogus HTTP usage"? No sweat, I'll just perform the same protocol piggyback trick as before, or similar.
Throw up some buffer-scrubbers to wipe that out (a really sound idea in any event, as it turns out)? I'll come up with.... something. Left as an exercise to the reader, not to encourage someone to go out and implement another of my whacky ideas...
As long as it's possible for me to have control over two host computers on two different networks, it's possible for me to craft some sort of protocol carried over IP that I can use to link those two networks together, provided that I've got Internet connections in both locations.
John Gilmore was right: "The Net interprets censorship as damage and routes around it"
As long as what you're DOING with the VPN is legal, I believe that having one should be as well. And even it it's not, well, there's just really not much you can do about it.
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