What is the dotted decimal equivalent of a /30 prefix length?

The dotted decimal equivalent of a /30 prefix length is 255.255.255.252.

To understand this, it’s important to grasp the concept of subnetting and how CIDR (Classless Inter-Domain Routing) notation works. A /30 prefix indicates that 30 bits of the IP address are used for the network part, leaving only 2 bits for host addresses.

In IPv4, there are a total of 32 bits. For a /30 subnet, the first 30 bits represent the network, and the last 2 bits can be used for host addresses. The binary representation for the subnet mask would be:

11111111.11111111.11111111.11111100

When converted to decimal, this binary value becomes 255.255.255.252. This subnet allows for 4 IP addresses (2^2) in total: 2 usable host addresses (after excluding the network and broadcast addresses), which is commonly used for point-to-point links.

Understanding the conversion from binary to decimal is crucial for interpreting subnet masks, as these values depict how many addresses are available within a given network segment. This knowledge is foundational in managing subnetting effectively in networks.