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VLSM (CIDR) Subnet Calculator

Variable Length Subnet Masking is a technique that allows network administrators to divide an IP address space to subnets of different sizes, unlike simple same-size subnetting. Learn more about VLSM

VLSM Subnet Calculator is intend for automate and simplify VLSM calculation process.

How to use: Enter major network address and prefix, like
Enter sizes (number of assignable ip addresses) of subnets to divide major network. You can specify subnetwork names instead of default.
You can change number of subnets at any time.

Major network
Name Size
Number of subnets:
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