UUUP Tools

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Subnet Calculator — IPv4 CIDR Planning Tool

Calculate subnet mask, network address, broadcast address, and usable host count from an IP and CIDR prefix for internal segmentation, Docker networks, and routing plans.

Quick switch→MAC Vendor Lookup
CIDRSubnetNetwork
Quick switch:MAC Vendor LookupIP Geo LookupTCP Flags Decoder

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Use cases

  • Plan Docker overlay ranges
  • Allocate enterprise internal routing blocks
  • Verify usable host counts for /20 and /24 networks

How to use

  1. Enter an IP address
  2. Choose or enter a CIDR prefix
  3. Review mask, broadcast, and host range

Example input and output

CIDR

192.168.1.10/24

Result

Mask 255.255.255.0, broadcast 192.168.1.255

FAQ

Does it support IPv6?

It currently targets IPv4 and common CIDR prefixes only.

How many usable hosts does /24 provide?

Excluding network and broadcast addresses, /24 usually leaves 254 usable host addresses.

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TCP Flags Decoder

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