No one ever called GRE or 6-in-4 a VPN, why is that!? Let me copy paste my other comment: Read the acronym carefully. It is virtual and it is a network. Not th

No one ever called GRE or 6-in-4 a VPN, why is that!? Let me copy paste my other comment: Read the acronym carefully. It is virtual and it is a network. Not the destination but the tunnel itself is the network that is private. It was described as such from the start and in no networking context have I ever heard otherwise (correct me if wrong please). Let's say you have an IPSec tunnel between a branch location and HQ site. The typical solution was GRE where you encapsulate it inside another IP packet that has public IPs only for the destination to decapsulate it. When VPNs came along they added privacy hence the name. In networking you are not connecting two networks. You are interconnecting three networks! the branch would have its own subnet so would HQ but the VPN also would have its subnet all routed as separate networks. The tunnel network getting privacy because it traverses untrusted networks (back in the day it wasn't typically the interent but ATM, frame relay,T1,etc... "directly" between sites), that's where term cloud comes from FYI the untrusted magic ISP network in the sky.