Subnet Masks (Plain English)

Subnet Masks (Plain English)

A subnet mask tells your network how big the IP range is. It’s another way to express CIDR.

Common examples

• 255.255.255.0 = /24 (256 total addresses)
• 255.255.255.128 = /25 (128 total addresses)
• 255.255.255.240 = /28 (16 total addresses)

Why it matters

The subnet mask determines:

• how many usable IPs you have
• which IPs belong to the same network
• how devices communicate locally

In Netory

You can enter networks using either:

• CIDR (recommended)
• Subnet mask

Netory converts both into the same IP pool math.