online CIDR and IP subnet calculator : Check host

121.254.138.0-121.254.139.255
121.254.138.0/23

121.254.140.0-121.254.143.255
121.254.140.0/22

121.254.144.0-121.254.159.255
121.254.144.0/20

121.254.160.0-121.254.175.255
121.254.160.0/20

121.254.176.0-121.254.183.255
121.254.176.0/21

121.254.184.0-121.254.185.255
121.254.184.0/23

121.254.186.0-121.254.186.255
121.254.186.0/24

IP subnet calculator 121.254.138.0-121.254.186.255