Series
Things worth reading in order.
3 series, 29 parts, 64,367 words — just under a third of everything here. Each one builds, so the site tracks which parts you have finished and where to pick up.
#net / 8 parts / 115 min
Networking, from cable to route
Eight parts that build up the Linux networking stack in the order it actually resolves: the physical link, addressing, routing decisions, then the tooling that inspects each layer.
#dc / 9 parts / 96 min
Inside the data center
Nine parts on the physical side of infrastructure — what a cage, a cross-connect and a pair of remote hands really are, written for people who only ever meet servers over SSH.
#lfs / 12 parts / 117 min
Linux From Scratch, start to finish
Twelve parts building a working Linux system from source — why you would, how the host toolchain bootstraps itself, and every package that stands between a partition and a login prompt.