Yes, it's possible.
To add IP address range you simply go to the Shield => Security Dashboard => IP Lists tab => IP Whitelist and copy the range into the box and click to add.
Please note that IP address ranges are supporting using CIDR notation for IPv4 addresses only.
CIDR IP addresses are composed of 2 sets of numbers:
- The network address is written as a prefix, like you would see a normal IP address, for example 188.8.131.52.
- The second part is the suffix which indicates how many bits are in the entire address, for example /12.
Putting it together, a CIDR IP address would look like this:
You can find more about this here: