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(also Classless Inter-Domain Routing)

CIDR definition

CIDR is a system that efficiently manages Internet Protocol addresses. Classless Inter-Domain Routing system replaced an older, more traditional class-based system to allocate IP addresses using variable-length subnet masks. It sustains IP address space and improves routing to manage networks and cybersecurity for various segmentation tasks and firewall configuration management. Moreover, CIDR is often used to define the IP address ranges in firewall rules, letting through or blocking specific ranges in internet protocol addresses to enhance network security.

See also: anti-malware

Reasons for using CIDR

Not only that, CIDR brings advantages like reducing the number of routing table entries, brings flexibility, and scalability, but it’s a valuable tool for managing networks. Here are some fair points on why it’s reasonable to consider using CIDR.

  • Improved routing scalability: CIDR is useful in large networks because it’s possible to scale up the routing tables. In other words, one single route entry can be represented as a range of IP addresses. And fewer routing tables means less weight for the routers.
  • Efficient IP address allocation: CIDR allows using IP addresses by enabling variable-length subnet masks. CIDR lets the network admins allocate IP addresses very precisely.
  • Renumbering and network reorganization: Using CIDR, the IP address renumbering process and network reorganization are simplified. That facilitates the change of the network prefix length. It has become more accessible and more convenient. That way, extensive modifications to the routing infrastructure are eliminated.
  • Upgraded network security: CIDR, let’s implement more granular access control (ACLs). So the administrators can create more specific rules and allow or deny traffic-based IP addresses, ranges, and subnet masks.
  • IP address aggregation: CIDR system allows aggregating IP addresses into larger blocks and reducing the number of route entries required in routers.