Classless Inter-Domain Routing (CIDR) is a method for allocating IP addresses and for IP routing. The Internet Engineering Task Force (IETF) introduced CIDR in 1993 to replace the previous classful network addressing architecture on the Internet. Wikipedia 
# What CIDR block am I on?
Lookup your IP address with ``` curl ifconfig.co ```
Add this output to Country IP Block's lookup to get the CIDR block it's assigned to. Lookup
Add to your Allowlist.