# Configure routing to access Multi-AZ file systems from on-premises
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**To configure AWS Transit Gateway for access to Multi-AZ file systems from on-premises**

If you have a Multi-AZ file system with an `EndpointIPv4AddressRange` or `EndpointIPv6AddressRange` that's outside your VPC's CIDR range, you need to set up additional routing in your AWS Transit Gateway to access your file system from peered or on-premises networks.
**Note**  
No additional Transit Gateway configuration is required for Single-AZ file systems or Multi-AZ file systems with an endpoint IP address range that's within your VPC's IP address range.

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

1. Choose the FSx for ONTAP file system for which you are configuring access from a peered network.

1. In **Network & security** copy the **Endpoint IPv4 or IPv6 address range**. 

1. Add a route to the Transit Gateway that routes traffic destined for this IP address range to your file system's VPC. For more information, see [Work with transit gateways](https://docs.aws.amazon.com/vpc/latest/tgw/working-with-transit-gateways.html) in the *Amazon VPC Transit Gateway User Guide*.

1. Confirm that you can access your FSx for ONTAP file system from the peered network.

**Important**  
To access a Multi-AZ file system using a Transit Gateway, each of the Transit Gateway's attachments must be created in a subnet whose route table is associated with your file system. Where you have separate Transit Gateway attachment subnets, you must also associate the route tables for those subnets with Amazon FSx so that they are updated with the Amazon FSx endpoint addresses.

To add a route table to your file system, see [Updating file systems](updating-file-system.md).