# Source: https://docs.datadoghq.com/security/code_security/iac_security/iac_rules/terraform/gcp/ip_aliasing_disabled.md

---
title: IP aliasing disabled
description: Datadog, the leading service for cloud-scale monitoring.
breadcrumbs: >-
  Docs > Datadog Security > Code Security > Infrastructure as Code (IaC)
  Security > IaC Security Rules > IP aliasing disabled
---

# IP aliasing disabled

{% callout %}
# Important note for users on the following Datadog sites: app.ddog-gov.com

{% alert level="danger" %}
This product is not supported for your selected [Datadog site](https://docs.datadoghq.com/getting_started/site). ().
{% /alert %}

{% /callout %}

## Metadata{% #metadata %}

**Id:** `c606ba1d-d736-43eb-ac24-e16108f3a9e0`

**Cloud Provider:** GCP

**Platform:** Terraform

**Severity:** Medium

**Category:** Insecure Configurations

#### Learn More{% #learn-more %}

- [Provider Reference](https://registry.terraform.io/providers/hashicorp/google/latest/docs/resources/container_cluster)

### Description{% #description %}

Kubernetes clusters on Google Kubernetes Engine (GKE) should be created with Alias IP ranges enabled by defining the `ip_allocation_policy` block and setting the `networking_mode` attribute to `"VPC_NATIVE"`. Without these settings, as shown in the example below, the cluster may fall back to legacy networking modes, which do not provide the same isolation or scalability benefits and increase the risk of network conflicts and unauthorized access:

```
resource "google_container_cluster" "example" {
  name               = "my-legacy-cluster"
  location           = "us-central1-a"
  initial_node_count = 3
  // Missing ip_allocation_policy and/or incorrect networking_mode
}
```

A secure configuration should include both `ip_allocation_policy` and `networking_mode = "VPC_NATIVE"`, as shown here:

```
resource "google_container_cluster" "example" {
  name               = "my-secure-cluster"
  location           = "us-central1-a"
  initial_node_count = 3
  ip_allocation_policy {}
  networking_mode = "VPC_NATIVE"
}
```

Failure to enforce Alias IP allocation can reduce network segmentation and may expose pods and services to unintended network access.

## Compliant Code Examples{% #compliant-code-examples %}

```terraform
#this code is a correct code for which the query should not find any result
resource "google_container_cluster" "negative1" {
  name               = "marcellus-wallace"
  location           = "us-central1-a"
  initial_node_count = 3
  ip_allocation_policy {

  }
  networking_mode = "VPC_NATIVE"

  timeouts {
    create = "30m"
    update = "40m"
  }
}
```

## Non-Compliant Code Examples{% #non-compliant-code-examples %}

```terraform
#this is a problematic code where the query should report a result(s)
resource "google_container_cluster" "positive1" {
  name               = "marcellus-wallace"
  location           = "us-central1-a"
  initial_node_count = 3

  timeouts {
    create = "30m"
    update = "40m"
  }
}

resource "google_container_cluster" "positive2" {
  name               = "marcellus-wallace"
  location           = "us-central1-a"
  initial_node_count = 3

  networking_mode = "VPC_NATIVE"

  timeouts {
    create = "30m"
    update = "40m"
  }
}

resource "google_container_cluster" "positive3" {
  name               = "marcellus-wallace"
  location           = "us-central1-a"
  initial_node_count = 3
  ip_allocation_policy {

  }
  networking_mode = "ROUTES"

  timeouts {
    create = "30m"
    update = "40m"
  }
}
```