https://blogs.damiendye.uk/en/tags/tap/ Recent content in Tap on Damien Dye's Blog Hugo en-GB Mon, 14 Sep 2026 15:00:00 +0100 https://blogs.damiendye.uk/en/networking/a-vpn-out-of-parts-and-what-egress-really-is/ Mon, 14 Sep 2026 15:00:00 +0100 https://blogs.damiendye.uk/en/networking/a-vpn-out-of-parts-and-what-egress-really-is/ A VPN is a virtual link plus a carrier, and Linux ships a program for each: pppd or a tap device, and netcat. Building it both ways — over TCP, UDP, TLS and DTLS, with zstd compression — shows what a VPN is made of, and what egress really is: once an attacker has root and outbound is open, the tunnel is already installed.