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ipPrefix - Generate the CIDR range for a given subnet

The ipPrefix function is very useful for working out the subnet in which an IP address belongs.

Syntax

ipPrefix(ip: string, subnetSize: number): string

Arguments

NameTypeRequiredDescription
ipstringtrueThe IP address to process
subnetSizenumbertrueThe number of mask bits in the subnet. For example, 10 will result in a CIDR range ending in /10

Example - Generating the CIDR range for a given IP in a subnet of known size

Consider the following document:

{
    "ip": "155.123.7.4"
}

To calculate the subnet for this IP, and assuming that we know the number of mask bits, we can use the ipPrefix function:

create ip_subnet from ipPrefix(ip, 10)

This results in the following document:

{
    "ip": "155.123.7.4",
    "ip_subnet": "155.64.0.0/10"
}