PrintableCharts
SUBNET MASKS

1 / 2 · mockup · corridor-glass

SUBNET MASKS

from /0 to /32: the mask, how many addresses a block holds, and how many of them go to hosts

Built as a memo rather than a table: the thing worth hanging it up for reads across the room, with the full reference in smaller type below it.

Three sizes in one archive — from a sheet on the fridge to a poster on the wall.

Premium$2.50

Payment and email are handled by Paddle. The download link arrives by email — no account, no password.

Formats
A4 · A3 · A2
What you get
Print-ready PDFs, one per size, with every letterform converted to outlines — nothing to install, nothing to shift.
Subject
code · reference · study

The prefix and the mask are one number written two ways: /26 and 255.255.255.192. The addresses column is the size of the block; the hosts column is how many of them can be handed out to machines.

THE TWO ADDRESSES THAT WERE MISSING

A point-to-point link has exactly two ends, yet until 2000 the shortest numbered subnet was a /30: four addresses, two of which are the network itself and the broadcast. Half of every such block went to nobody.

RFC 3021 allowed a /31 on such links: two addresses, both of them usable, and no broadcast — whatever one end transmits is received by the other anyway. That is exactly the two addresses out of four that used to disappear.

On the sheet

  • The prefix and the mask are one number written two ways: /26 and 255.255.255.192. The addresses column is the size of the block; the hosts column is how many of them can be handed out to machines.
  • Colour carries meaning, but meaning never rests on colour alone — the sheet reads in black and white.
  • Nothing about how it was made: the sheet carries only what the reader needs.

Printing

  • Three sizes in the archive: A4 — 210×297 mm, A3 — 297×420 mm, A2 — 420×594 mm.
  • All text is converted to outlines. No fonts to install, and nothing shifts on another machine.
  • White background and sparing fills — it prints on a home printer without draining the cartridge.
  • Margins of at least 10 mm: a home printer cannot print to the edge.
  • No stroke thinner than 0.3 mm, so nothing disappears in print.

Why the numbers can be trusted. Every countable number here is computed from data rather than typed in, and the sheet must pass 8 independent checks before it is allowed to build — how many items there are, the order they come in, and the claim in the highlighted box itself. If one fails, there is no file.

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