IP Subnet Calculator
IP address: 10.1.1.5
IP class: A
Subnet mask: 255.255.255.0
Subnet address: 10.1.1.0
Bits in mask: 24
Number of hosts: 254
This subnet calculator can help you with the following tasks:
- Identify subnet parameters for a given IP address and subnet mask (or CIDR prefix).
- Display subnet parameters for a number of consecutive subnets of the specified length.
CIDR stands for Classless Inter-Domain Routing. CIDR refers to a method for allocating IP addresses and routing Internet Protocol packets.
Number of hosts on a /31 subnet:
Generally, within a subnet, two host addresses - all-zeros and one all-ones are reserved as network address and
broadcast, respectively. The same approach applied to a /31 subnet with only two possible addresses in the host identifier
would leave no usable addresses for host assignment.
RFC3021: Using 31-Bit Prefixes on IPv4 Point-to-Point Links
allows assignment of the all-zeros and one all-ones IP addresses to hosts on point-to-point links.