# Enable zonal shift for your Network Load Balancer
<a name="enable-zonal-shift"></a>

Zonal shift is disabled by default and must be enabled on each Network Load Balancer. This ensures that you can start a zonal shift using only the specific Network Load Balancers that you want. For more information, see [Zonal shift for your Network Load Balancer](zonal-shift.md).

**Prerequisites**

If you enable cross-zone load balancing for the load balancer, every target group attached to the load balancer must meet the following requirements before you can enable zonal shift.
+ The target group protocol must be `TCP` or `TLS`.
+ The target group type must not be `alb`.
+ [Connection termination for unhealthy targets](edit-target-group-attributes.md#unhealthy-target-connection-termination) must be disabled.
+ The `load_balancing.cross_zone.enabled` target group attribute must be `true` or `use_load_balancer_configuration` (the default).

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#### [ Console ]

**To enable zonal shift**

1. Open the Amazon EC2 console at [https://console.aws.amazon.com/ec2/](https://console.aws.amazon.com/ec2/).

1. On the navigation pane, under **Load Balancing**, choose **Load Balancers**.

1. Select the Network Load Balancer.

1. On the **Attributes** tab, choose **Edit**.

1. Under **Availability Zone routing configuration**, for **ARC zonal shift integration**, choose **Enable**.

1. Choose **Save changes**.

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#### [ AWS CLI ]

**To enable zonal shift**  
Use the [modify-load-balancer-attributes](https://docs.aws.amazon.com/cli/latest/reference/elbv2/modify-load-balancer-attributes.html) command with the `zonal_shift.config.enabled` attribute.

```
aws elbv2 modify-load-balancer-attributes \
    --load-balancer-arn load-balancer-arn \
    --attributes "Key=zonal_shift.config.enabled,Value=true"
```

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#### [ CloudFormation ]

**To enable zonal shift**  
Update the [AWS::ElasticLoadBalancingV2::LoadBalancer](https://docs.aws.amazon.com/AWSCloudFormation/latest/TemplateReference/aws-resource-elasticloadbalancingv2-loadbalancer.html) resource to include the `zonal_shift.config.enabled` attribute.

```
Resources:
  myLoadBalancer:
    Type: 'AWS::ElasticLoadBalancingV2::LoadBalancer'
    Properties:
      Name: my-nlb
      Type: network
      Scheme: internal
      Subnets: 
        - !Ref subnet-AZ1
        - !Ref subnet-AZ2
      SecurityGroups: 
        - !Ref mySecurityGroup
      LoadBalancerAttributes:
        -Key: "zonal_shift.config.enabled"
         Value: "true"
```

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