# CIDR Block CIDR stands for Classless Inter-Domain Routing, which is a method of allocating IP addresses and routing Internet Protocol (IP) packets. A CIDR block is a range of IP addresses that can be assigned to devices on a network. In CIDR notation, a CIDR block is represented by an IP address followed by a forward slash (/) and a number that indicates the number of significant bits in the network address. For example, a CIDR block of 10.0.0.0/24 would indicate that the network address is 10.0.0.0 and that the first 24 bits of the IP address are used for the network portion of the address, leaving the last 8 bits for device addresses. CIDR blocks are used to create subnets within a network, which can be used to partition a larger network into smaller, more manageable segments. By assigning CIDR blocks to subnets, network administrators can control IP address allocation and routing within the network. CIDR blocks are also used to allocate IP addresses to virtual private cloud (VPC) networks in public cloud environments. In this case, the CIDR block is used to define the IP address range for the VPC and the subnets within it. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.console.zenlayer.com/glossary/c/cidr-block.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.