|Subnet addr||First host||Last host||Subnet mask||Broadcast|
This subnet calculator can help you with the following tasks:
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.
Subnet Mask Table