Can you explain what a network mask is and how it is used in IP addressing?

A network mask is a bitmask used to divide an IP address into two parts: network and host.

In IPv4, the network mask is usually written as four octets, for example, 255.255.255.0, or in CIDR format, for example, /24.

It determines which part of the IP address belongs to the network address and which part belongs to a specific device (host) within that network.

For example, if you have an IP address 192.168.1.10 with a mask of 255.255.255.0, then the first three octets (192.168.1) are the network address, and the last octet (10) is the host address within that network.

The network mask allows routers and devices to understand which addresses are in the local network and which are in other networks, and to route traffic accordingly.

Example:

• IP: 192.168.1.10
• Mask: 255.255.255.0 (/24)
• Network address: 192.168.1.0
• Host range: 192.168.1.1 — 192.168.1.254

Thus, the network mask is a key element for organizing and routing IP traffic.