online CIDR and IP subnet calculator : Check host

121.240.230.0-121.240.231.255
121.240.230.0/23

121.240.232.0-121.240.239.255
121.240.232.0/21

121.240.240.0-121.240.255.255
121.240.240.0/20

121.242.0.0-121.242.15.255
121.242.0.0/20

121.242.16.0-121.242.19.255
121.242.16.0/22

121.242.20.0-121.242.20.255
121.242.20.0/24

121.241.0.0-121.241.255.255
121.241.0.0/16

IP subnet calculator 121.240.230.0-121.242.20.255