The subnet notation 255.255.255.0 represents a subnet mask in dotted-decimal format, commonly used in IPv4 networking to define the size and boundaries of a subnet. Each octet (segment separated by dots) in the subnet mask specifies eight bits, totaling 32 bits for IPv4 addresses. In this notation:
- The first three octets (255.255.255) are all set to 255, indicating that the first 24 bits of the subnet mask are set to “1”.
- The last octet (0) is set to 0, indicating that the remaining 8 bits are set to “0”, allowing for host addresses within the subnet.
If a network is configured with a subnet mask of 255.255.255.0 (or /24 in CIDR notation), it signifies that the first 24 bits of an IPv4 address are dedicated to identifying the network portion, while the remaining 8 bits are available for host addresses. This provides up to 254 usable IP addresses within the subnet, excluding the network address (all host bits set to 0) and the broadcast address (all host bits set to 1).
The subnet prefix length for a subnet mask of 255.255.255.0 is 24 bits. This is because the subnet mask 255.255.255.0 corresponds to a network prefix of 24 bits in length. In CIDR notation, this is denoted as /24, where the first 24 bits of an IP address indicate the network portion, and the remaining bits denote the host portion.
In subnet mask notation, 255.255.255.0 indicates that the first three octets (24 bits) are set to “1”, designating the network address, while the last octet (8 bits) is set to “0”, allowing for host addresses within the subnet. This configuration is commonly used in small to medium-sized networks to efficiently allocate IP addresses and manage network traffic.
When a router receives traffic with an IP address, it uses the subnet mask (such as 255.255.255.0) to determine how to handle that traffic. Specifically, the subnet mask 255.255.255.0 tells the router that the first three octets (24 bits) of an IP address represent the network portion, and the remaining octet (8 bits) identifies individual hosts within that network. This information allows the router to route packets within the local network based on their destination IP addresses, ensuring that traffic is correctly directed to its intended destination or forwarded to other networks as needed.
