CIDR Block
Classless Inter-Domain Routing notation
It is used to to identify hosts and networks inside an existing network.
To create a network, we need to take consecutive segments of the whole IP addressing space. The CIDR notation help identify the network and hosts.
An IPv4 address consists of 32 bits. containing an IP address, a '/' character and a decimal from 0 to 32 . Eg.: 0.0.0.0/16
Creating subnets is about creating commonalities 201.105.7.34/24 is in the same network as 201.105.7.1/24. The suffix signals that only the first 24 bits of the network component are counted
This starts to make sense when we transform the decimal into binary:
201.105.7.34 corresponds to 11001001 01101001 00000111 00100010
With /24 at the end we count only the first 24 bits for an IP range: 11001001 01101001 00000111 Leaving the last 8 bits as a range of addresses to be assigned. That computes to a total of
Links to : VPC
Sources:
https://www.ionos.com/digitalguide/server/know-how/cidr-classless-inter-domain-routing/
https://blogs.mulesoft.com/api-integration/security/how-to-choose-the-cidr-block-for-your-vpc/