56 lines
1.8 KiB
Markdown
56 lines
1.8 KiB
Markdown
---
|
|
layout: "functions"
|
|
page_title: "cidrhost - Functions - Configuration Language"
|
|
sidebar_current: "docs-funcs-ipnet-cidrhost"
|
|
description: |-
|
|
The cidrhost function calculates a full host IP address within a given
|
|
IP network address prefix.
|
|
---
|
|
|
|
# `cidrhost` Function
|
|
|
|
-> **Note:** This page is about Terraform 0.12 and later. For Terraform 0.11 and
|
|
earlier, see
|
|
[0.11 Configuration Language: Interpolation Syntax](../../configuration-0-11/interpolation.html).
|
|
|
|
`cidrhost` calculates a full host IP address for a given host number within
|
|
a given IP network address prefix.
|
|
|
|
```hcl
|
|
cidrhost(prefix, hostnum)
|
|
```
|
|
|
|
`prefix` must be given in CIDR notation, as defined in
|
|
[RFC 4632 section 3.1](https://tools.ietf.org/html/rfc4632#section-3.1).
|
|
|
|
`hostnum` is a whole number that can be represented as a binary integer with
|
|
no more than the number of digits remaining in the address after the given
|
|
prefix. For more details on how this function interprets CIDR prefixes and
|
|
populates host numbers, see the worked example for
|
|
[`cidrsubnet`](./cidrsubnet.html).
|
|
|
|
Conventionally host number zero is used to represent the address of the
|
|
network itself and the host number that would fill all the host bits with
|
|
binary 1 represents the network's broadcast address. These numbers should
|
|
generally not be used to identify individual hosts except in unusual
|
|
situations, such as point-to-point links.
|
|
|
|
This function accepts both IPv6 and IPv4 prefixes, and the result always uses
|
|
the same addressing scheme as the given prefix.
|
|
|
|
## Examples
|
|
|
|
```
|
|
> cidrhost("10.12.127.0/20", 16)
|
|
10.12.112.16
|
|
> cidrhost("10.12.127.0/20", 268)
|
|
10.12.113.12
|
|
> cidrhost("fd00:fd12:3456:7890:00a2::/72", 34)
|
|
fd00:fd12:3456:7890::22
|
|
```
|
|
|
|
## Related Functions
|
|
|
|
* [`cidrsubnet`](./cidrsubnet.html) calculates a subnet address under a given
|
|
network address prefix.
|