Prefixġ IPv6 subnet with up to 18,446,744,073,709,551,616 IPv6 host addressesĪ network site that is assigned a /48 prefix can use prefixes in the range /49 to /64 to define valid subnets. This table shows common IPv6 network prefixes and the number of IPv6 subnets and IPv6 addresses they support. The CIDR notation works exactly the same as with IPv4, which means if you have a /48, that means the first 48 bits of the address are the prefix. The prefix is expressed as a slash (/) followed by the prefix size, which is a decimal number between 1 and 128. In IPv6, slash notation is used to represent the network identifier prefix for an IPv6 network.

This table shows common network masks and their equivalents in slash notation. Write the original IP address, a forward slash (/), and then the number from Step 2.In this example, there are twenty-four (24). In this example, the binary representation of 255.255.255.0 is: The total is the subnet mask number.įor example, to write the IPv4 address 192.168.42.23 with a subnet mask of 255.255.255.0 in slash notation: Convert the decimal representation of the subnet mask to a binary representation.When you use slash notation, you write the IP address, a forward slash (/), and the subnet mask number.

Slash notation is a compact way to show or write an IPv4 subnet mask. You use slash notation differently for IPv4 and IPv6 addresses. Your Firebox uses slash notation, also known as CIDR (Classless Inter-Domain Routing) notation, for many purposes, such as policy configuration.

Class b subnet mask table