IPv4 Subnet Calculator

This calculator and tool allows you to type an IP address in and get information on a particular subnet. Enter an IP or range in CIDR notation.

Network: 2.1.128.66/31
Addresses: 2 (2¹)
First IP: 2.1.128.66 (66.128.1.2.in-addr.arpa)
Last IP: 2.1.128.67 (67.128.1.2.in-addr.arpa)

/8 Operated By: RIPE NCC

Related Networks

2.0.0.0/8
1.0.0.0/8
3.0.0.0/8
2.1.128.64/30
2.1.128.66/32
2.1.128.67/32

You can also use some of the other examples such as:

0.0.0.0/0
1.0.0.0/8
127.0.0.1
30.0.0.0/8
192.168.0.0/16