CIDR Utility Tool | IP Address Guide — use this to put the correct net that you want to block in your Firewall
When mega stressed about DDOS jerks, this page is really helpful to tell you what number to block in your firewall. in AWS out it in https://console.aws.amazon.com/vpc/
CIDRCIDR is the short for Classless Inter-Domain Routing, an IP addressing scheme that replaces the older system based on classes A, B, and C. A single IP address can be used to designate many unique IP addresses with CIDR. A CIDR IP address looks like a normal IP address except that it ends with a slash followed by a number, called the IP network prefix. CIDR addresses reduce the size of routing tables and make more IP addresses available within organizations
Originally published at Charming Web Design.