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Subnetting with the Box Method

For visual learners.

For a /24 network, thats 256 addresses, or … this box.

Start With A /24

Write the first IP in the top corner, the last IP in the bottom corner.

0255

Cut In Half (1)

Write the last number in the bottom corner, next number in the top corner.

0128127255

Two /25 networks.

Cut In Half (2)

01286364127255
  • One /25
  • Two /26 networks.

Cut In Half (3)

0321283163649291127255
  • One /25
  • Four /27

Cut In Half (4)

03212831636492791078010891127255
  • One /25
  • Two /27
  • Four /28
Last Modified • Friday, June 12, 2026. 3:54 am UTC+00:00 • Commit: 5f6d3fd