Subnet mask

A subnet mask is a set of IP addresses used to build numerous sub-networks within an extensive IP network.

What is the subnet mask?

A subnet mask is a 32-bit address that separates an IP address into network bits that determine the network and host bits that identify the host device connected to that network. It represents a set of IP addresses that a subnet can utilize, whereas a subnet is a smaller network within a more extensive network.

Subnet masks are used internally in networks. Subnet masks are used by routing devices or switches to direct data packets to their intended destinations. Data packets sent over the Internet or any network do not include the subnet mask but show the destination’s IP address. To deliver the data packet to the correct location, routers compare the destination IP address with the subnet mask of the data packet.

What is a 255.255 255.0 subnet mask?

The most common subnet mask on devices linked to IPv4 networks is 255.255.255.0.

Subnets serve as virtual gates that divide a block of IP addresses into smaller parts. This method reduces network congestion and enables granular access across subnets. A subnet mask is used to identify individual subnets.

Traditional subnets used classed networks, which split IP addresses into five classes (Class A/B/C/D/E) based on the IP address number.

The subnet mask 255.255.255.0 generates a 32-bit binary value such as:

11111111 22222222 33333333 00000000

The 0 digits of this mask span the subnet’s IP range, which is 8 bits or up to 256 addresses.

Where do I find my subnet mask?

If you use ​​Windows, you may find your subnet mask using the following instructions:

1. Go to the “Control Panel” and then the “Network and Sharing Centre.”
2. Click on your network name, then “Details.”
3. You’ll find the subnet mask as well as other network information.

Follow these instructions to find your subnet mask on macOS.

1. Click on “System Preferences” and then “Network.”
2. Select your network and then select “Advanced.”
3. When you click the TCP/IP tab, your IP address and subnet mask will be displayed.

Android users can find their subnet mask with the following easy steps:

1. Click on “Settings,” then “Wireless & Networks,” then “WiFi.”
2. Tap on the network you’re currently connected to.
3. You’ll find the subnet mask as well as other network information.

On iOS, take these procedures to find your subnet mask:

1. Go to “Settings”, then “WiFi.”
2. Locate the network you are linked to and select the “i” icon.
3. You’ll find the subnet mask as well as other network information.

Is a subnet mask the same as a router?

A subnet mask is not the same as a router; instead, the mask defines your subnet to the router. A subnet mask is equivalent to an IP address but is only used internally within a network. 

Routers use subnet masks to route data packets to their intended destination. Subnet masks are not displayed in data packets that transit across the Internet; instead, such packets indicate the destination IP address, which a router will pair with a subnet.