VPN basics

This is part of the Semicolon&Sons Code Diary - consisting of lessons learned on the job. You're in the networking category.

Last Updated: 2021-05-16

Purpose

Join two trusted networks (each of one or more machines) across an untrusted intermediate network - as if hooking them up with a secure secret cable.

What can be seen from the outside, i.e. from the untrusted network?

Merely that these machines are communicating and may form part of a VPN. Therefore an outsider might understand that there are trust relationships, but have no actual info about the traffic itself. Even the type of transport protocol (UDP/TCP/other) is hidden form prying eyes.

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