online CIDR and IP subnet calculator : Check host

165.91.1.0-165.91.1.255
165.91.1.0/24

165.91.2.0-165.91.3.255
165.91.2.0/23

165.91.4.0-165.91.7.255
165.91.4.0/22

165.91.8.0-165.91.15.255
165.91.8.0/21

165.91.16.0-165.91.31.255
165.91.16.0/20

165.91.32.0-165.91.63.255
165.91.32.0/19

165.91.64.0-165.91.127.255
165.91.64.0/18

165.91.128.0-165.91.255.255
165.91.128.0/17

IP subnet calculator 165.91.1.0-165.91.255.255