TLS on Aperture Zone

Layers 5 and 6: The Phantom Layers

Sun, 02 Aug 2026 00:00:00 +0000

Fifth and sixth layers. After the cable, the MAC addresses, the IP, and TCP, logically, we should be talking about the session layer, followed by the presentation layer.

Except that we have to be honest: these two layers are practically nonexistent.

Not in the sense that they’re useless—but in the sense that, in the network you manage every day, no one implements them as such. There is no “Layer 6 protocol” the way there is a Layer 3 (IP) or Layer 4 (TCP). These are two layers that the OSI model envisaged, that theory describes in detail, and that reality has simply absorbed elsewhere.

Layer 7: The Application — HTTP, DNS, DHCP, and the Top of the Stack

Tue, 04 Aug 2026 00:00:00 +0000

Seventh and final layer. We started with the cable, we went through MAC addresses, IP and routing, TCP and ports, and we found that layers 5 and 6 were phantom layers. Here we are at the top.

And the top is where everyone lives. Layer 7 is what you see: the browser loading a page, an email being sent, a domain name being resolved, the machine receiving its IP address at startup. This is the application layer—the only one the user interacts with directly, and by far the richest in protocols.

From a Homemade PKI to Step-CA: Moving Away from Manual Signatures (Part 1)

Mon, 24 Aug 2026 00:00:00 +0000

Pendant lontgemp, ma PKI interne a reposé sur une autorité de certification OpenSSL pilotée à la main : une racine, des certificats de deux ans signés un par un. Ça marchait — jusqu'à ce que le nombre de services rende le modèle intenable. Cette première partie raconte la bascule vers step-ca : comment réutiliser la racine existante pour ne pas casser la confiance déjà déployée, comment passer à des certificats courts renouvelés automatiquement, et comment industrialiser le motif sur toute la flotte sans transformer chaque machine en corvée.