How it works
Starting at the first address, the converter takes the largest block that starts there and does not pass the end, then repeats. A range that does not line up with block boundaries needs several blocks: 192.0.2.5 to 192.0.2.20 becomes five.
Uses
Firewall and cloud security rules, web server allow lists and route filters usually accept CIDR only. Registry records and logs often give ranges.
Questions
- Does it work for IPv6?
- Yes, for any range where both ends are the same version.