Subnet IPv4 CIDR Address Blocks

« Return to

Please select a block of IP addresses below to view the "" IPv4 CIDR subnet mask range and related neighborhood IP address listings. This includes all listings from to

What is an IP Address Subnet?

An IP Address Subnet, also known as a "subnetwork", is the efficient allocation of an IP network in blocks of IP addresses. Class A Blocks end with "/8" and contain 16 million IP addresses. Class B Blocks end with "/16" and contain 65,000 IP addresses. Class C Blocks end with "/24" and support a maximum of 254 IP addresses.

  • Class A Example - - 16 Million Hosts
  • Class B Example - - 65,000 Hosts
  • Class C Example - - 254 Hosts
Lookup IP Address

What is CIDR notation?

CIDR format, or "Classless Inter-Domain Routing", released in 1993, is the industry standard for displaying IP addresses and their related subnets. It consists of a network prefix and the significant bits which determines the size of the IP block. Significant bits are in 8-bit groups that form Class A, B, and C blocks of IP addresses. An example of CIDR format is "", which indicates there are 65,000 hosts in this range from "" to "".

API Lookup Access

IP Reputation API Lookups

Threat & Abuse Network

Largest Threat & Abuse Network

Fraud Prevention Detection

Industry Leading Fraud Prevention

Ready to eliminate fraud?

Start fighting fraud in minutes!

Schedule a Demo Sign Up »

Get Started with 5,000 Free Lookups Per Month!