Write the subnet mask for the prefix /26 in dotted-quad notation.

LPIC-1 Exam 102-500, objective 109. Networking fundamentals medium

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Answer

Type the answer.

Accepted answer

Case sensitive — Linux is, and grading LS as ls would teach a falsehood.

Why

A /26 sets the first 26 bits: the fourth octet is 11000000 in binary, which is 192. That leaves 6 host bits, so each /26 block holds 64 addresses (62 usable) and the blocks begin at .0, .64, .128 and .192. The last-octet values for /25 to /32 run 128, 192, 224, 240, 248, 252, 254, 255.

Where this comes from

Cited
LPI exam objective 109.1
What it says
Convert a CIDR prefix length to a dotted-quad subnet mask.

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