Configure a VNet-to-VNet VPN gateway connection by using the Azure portal

This article helps you connect virtual networks (VNets) by using the VNet-to-VNet connection type. Virtual networks can be in different regions and from different subscriptions. When you connect VNets from different subscriptions, the subscriptions don't need to be associated with the same Active Directory tenant.

v2v diagram

The steps in this article apply to the Azure Resource Manager deployment model and use the Azure portal. You can create this configuration with a different deployment tool or model by using options that are described in the following articles:

About connecting VNets

The following sections describe the different ways to connect virtual networks.

VNet-to-VNet

Configuring a VNet-to-VNet connection is a simple way to connect VNets. When you connect a virtual network to another virtual network with a VNet-to-VNet connection type (VNet2VNet), it's similar to creating a Site-to-Site IPsec connection to an on-premises location. Both connection types use a VPN gateway to provide a secure tunnel with IPsec/IKE and function the same way when communicating. However, they differ in the way the local network gateway is configured.

When you create a VNet-to-VNet connection, the local network gateway address space is automatically created and populated. If you update the address space for one VNet, the other VNet automatically routes to the updated address space. It's typically faster and easier to create a VNet-to-VNet connection than a Site-to-Site connection.

Site-to-Site (IPsec)

If you're working with a complicated network configuration, you may prefer to connect your VNets by using a Site-to-Site connection instead. When you follow the Site-to-Site IPsec steps, you create and configure the local network gateways manually. The local network gateway for each VNet treats the other VNet as a local site. These steps allow you to specify additional address spaces for the local network gateway to route traffic. If the address space for a VNet changes, you must manually update the corresponding local network gateway.

VNet peering

You can also connect your VNets by using VNet peering. VNet peering doesn't use a VPN gateway and has different constraints. Additionally, VNet peering pricing is calculated differently than VNet-to-VNet VPN Gateway pricing. For more information, see VNet peering.

Why create a VNet-to-VNet connection?

You may want to connect virtual networks by using a VNet-to-VNet connection for the following reasons:

Cross region geo-redundancy and geo-presence

  • You can set up your own geo-replication or synchronization with secure connectivity without going over internet-facing endpoints.
  • With Azure Traffic Manager and Azure Load Balancer, you can set up highly available workload with geo-redundancy across multiple Azure regions. For example, you can set up SQL Server Always On availability groups across multiple Azure regions.

Regional multi-tier applications with isolation or administrative boundaries

  • Within the same region, you can set up multi-tier applications with multiple virtual networks that are connected together because of isolation or administrative requirements.

VNet-to-VNet communication can be combined with multi-site configurations. These configurations lets you establish network topologies that combine cross-premises connectivity with inter-virtual network connectivity, as shown in the following diagram:

About connections

This article shows you how to connect VNets by using the VNet-to-VNet connection type. When you follow these steps as an exercise, you can use the following example settings values. In the example, the virtual networks are in the same subscription, but in different resource groups. If your VNets are in different subscriptions, you can't create the connection in the portal. Use PowerShell or CLI instead. For more information about VNet-to-VNet connections, see VNet-to-VNet FAQ.

Example settings

Values for VNet1:

  • Virtual network settings

    • Name: VNet1
    • Address space: 10.1.0.0/16
    • Subscription: Select the subscription you want to use.
    • Resource group: TestRG1
    • Location: East US
    • Subnet
      • Name: FrontEnd
      • Address range: 10.1.0.0/24
    • Gateway subnet:
      • Name: GatewaySubnet is autofilled
      • Address range: 10.1.255.0/27
  • Virtual network gateway settings

    • Name: VNet1GW
    • Gateway type: Select VPN.
    • VPN type: Select Route-based.
    • SKU: Select the gateway SKU you want to use.
    • Public IP address name: VNet1GWpip
    • Connection
      • Name: VNet1toVNet4
      • Shared key: You can create the shared key yourself. When you create the connection between the VNets, the values must match. For this exercise, use abc123.

Values for VNet4:

  • Virtual network settings

    • Name: VNet4
    • Address space: 10.41.0.0/16
    • Subscription: Select the subscription you want to use.
    • Resource group: TestRG4
    • Location: West US
    • Subnet
      • Name: FrontEnd
      • Address range: 10.41.0.0/24
    • GatewaySubnet
      • Name: GatewaySubnet is autofilled
      • Address range: 10.41.255.0/27
  • Virtual network gateway settings

    • Name: VNet4GW
    • Gateway type: Select VPN.
    • VPN type: Select Route-based.
    • SKU: Select the gateway SKU you want to use.
    • Public IP address name: VNet4GWpip
    • Connection
      • Name: VNet4toVNet1
      • Shared key: You can create the shared key yourself. When you create the connection between the VNets, the values must match. For this exercise, use abc123.

Create and configure VNet1

If you already have a VNet, verify that the settings are compatible with your VPN gateway design. Pay particular attention to any subnets that may overlap with other networks. Your connection won't work properly if you have overlapping subnets.

To create a virtual network

You can create a VNet with the Resource Manager deployment model and the Azure portal by following these steps. For more information about virtual networks, see Virtual Network overview.

Note

When using a virtual network as part of a cross-premises architecture, be sure to coordinate with your on-premises network administrator to carve out an IP address range that you can use specifically for this virtual network. If a duplicate address range exists on both sides of the VPN connection, traffic will route in an unexpected way. Additionally, if you want to connect this virtual network to another virtual network, the address space cannot overlap with the other virtual network. Plan your network configuration accordingly.

  1. Sign in to the Azure portal.

  2. In Search resources, service, and docs (G+/), type virtual network.

    Locate Virtual Network resource page

  3. Select Virtual Network from the Marketplace results.

    Select virtual network

  4. On the Virtual Network page, select Create.

    virtual network page

  5. Once you select Create, the Create virtual network page opens.

  6. On the Basics tab, configure Project details and Instance details VNet settings.

    Basics tab When you fill in the fields, you see a green check mark when the characters you enter in the field are validated. Some values are autofilled, which you can replace with your own values:

    • Subscription: Verify that the subscription listed is the correct one. You can change subscriptions by using the drop-down.
    • Resource group: Select an existing resource group, or click Create new to create a new one. For more information about resource groups, see Azure Resource Manager overview.
    • Name: Enter the name for your virtual network.
    • Region: Select the location for your VNet. The location determines where the resources that you deploy to this VNet will live.
  7. On the IP Addresses tab, configure the values. The values shown in the examples below are for demonstration purposes. Adjust these values according to the settings that you require.

    IP addresses tab

    • IPv4 address space: By default, an address space is automatically created. You can click the address space to adjust it to reflect your own values. You can also add additional address spaces.
    • IPv6: If your configuration requires IPv6 address space, select the Add IPv6 address space box to enter that information.
    • Subnet: If you use the default address space, a default subnet is created automatically. If you change the address space, you need to add a subnet. Select + Add subnet to open the Add subnet window. Configure the following settings and then select Add to add the values:
      • Subnet name: In this example, we named the subnet "FrontEnd".
      • Subnet address range: The address range for this subnet.
  8. On the Security tab, at this time, leave the default values:

    • DDos protection: Basic
    • Firewall: Disabled
  9. Select Review + create to validate the virtual network settings.

  10. After the settings have been validated, select Create.

Create the VNet1 gateway

In this step, you create the virtual network gateway for your VNet. Creating a gateway can often take 45 minutes or more, depending on the selected gateway SKU. If you're creating this configuration as an exercise, see the Example settings.

The virtual network gateway uses specific subnet called the gateway subnet. The gateway subnet is part of the virtual network IP address range that you specify when configuring your virtual network. It contains the IP addresses that the virtual network gateway resources and services use.

When you create the gateway subnet, you specify the number of IP addresses that the subnet contains. The number of IP addresses needed depends on the VPN gateway configuration that you want to create. Some configurations require more IP addresses than others. We recommend that you create a gateway subnet that uses a /27 or /28.

If you see an error that specifies that the address space overlaps with a subnet, or that the subnet is not contained within the address space for your virtual network, check your VNet address range. You may not have enough IP addresses available in the address range you created for your virtual network. For example, if your default subnet encompasses the entire address range, there are no IP addresses left to create additional subnets. You can either adjust your subnets within the existing address space to free up IP addresses, or specify an additional address range and create the gateway subnet there.

To create a virtual network gateway

  1. From the Azure portal menu, select Create a resource.

    Create a resource in the Azure portal

  2. In the Search the Marketplace field, type 'Virtual Network Gateway'. Locate Virtual network gateway in the search return and select the entry. On the Virtual network gateway page, select Create. This opens the Create virtual network gateway page.

  3. On the Basics tab, fill in the values for your virtual network gateway.

    Create virtual network gateway page fields

    Create virtual network gateway page fields

    Project details

    • Subscription: Select the subscription you want to use from the dropdown.
    • Resource Group: This setting is autofilled when you select your virtual network on this page.

    Instance details

    • Name: Name your gateway. Naming your gateway not the same as naming a gateway subnet. It's the name of the gateway object you are creating.
    • Region: Select the region in which you want to create this resource. The region for the gateway must be the same as the virtual network.
    • Gateway type: Select VPN. VPN gateways use the virtual network gateway type VPN.
    • VPN type: Select the VPN type that is specified for your configuration. Most configurations require a Route-based VPN type.
    • SKU: Select the gateway SKU from the dropdown. The SKUs listed in the dropdown depend on the VPN type you select. For more information about gateway SKUs, see Gateway SKUs.
    • Generation: For information about VPN Gateway Generation, see Gateway SKUs.
    • Virtual network: From the dropdown, select the virtual network to which you want to add this gateway.
    • Gateway subnet address range: This field only appears if your VNet doesn't have a gateway subnet. If possible, make the range /27 or larger (/26,/25 etc.). We don't recommend creating a range any smaller than /28. If you already have a gateway subnet, you can view GatewaySubnet details by navigating to your virtual network. Click Subnets to view the range. If you want to change the range, you can delete and recreate the GatewaySubnet.

    Public IP address: This setting specifies the public IP address object that gets associated to the VPN gateway. The public IP address is dynamically assigned to this object when the VPN gateway is created. The only time the Public IP address changes is when the gateway is deleted and re-created. It doesn't change across resizing, resetting, or other internal maintenance/upgrades of your VPN gateway.

    • Public IP address: Leave Create new selected.
    • Public IP address name: In the text box, type a name for your public IP address instance.
    • Assignment: VPN gateway supports only Dynamic.

    Active-Active mode: Only select Enable active-active mode if you are creating an active-active gateway configuration. Otherwise, leave this setting unselected.

    Leave Configure BGP ASN deselected, unless your configuration specifically requires this setting. If you do require this setting, the default ASN is 65515, although this can be changed.

  4. Select Review + create to run validation. Once validation passes, select Create to deploy the VPN gateway. A gateway can take up to 45 minutes to fully create and deploy. You can see the deployment status on the Overview page for your gateway.

After the gateway is created, you can view the IP address that has been assigned to it by looking at the virtual network in the portal. The gateway appears as a connected device.

Important

When working with gateway subnets, avoid associating a network security group (NSG) to the gateway subnet. Associating a network security group to this subnet may cause your Virtual Network gateway(VPN, Express Route gateway) to stop functioning as expected. For more information about network security groups, see What is a network security group?

Create and configure VNet4

After you've configured VNet1, create VNet4 and the VNet4 gateway by repeating the previous steps and replacing the values with VNet4 values. You don't need to wait until the virtual network gateway for VNet1 has finished creating before you configure VNet4. If you're using your own values, make sure the address spaces don't overlap with any of the VNets to which you want to connect.

Configure the VNet1 gateway connection

When the virtual network gateways for both VNet1 and VNet4 have completed, you can create your virtual network gateway connections. In this section, you create a connection from VNet1 to VNet4. These steps work only for VNets in the same subscription. If your VNets are in different subscriptions, you must use PowerShell to make the connection. However, if your VNets are in different resource groups in the same subscription, you can connect them by using the portal.

  1. In the Azure portal, select All resources, enter virtual network gateway in the search box, and then navigate to the virtual network gateway for your VNet. For example, VNet1GW. Select the gateway to open the Virtual network gateway page. Under Settings, select Connections.

    Connections page

  2. Select +Add to open the Add connection page.

    Add connection

  3. On the Add connection page, fill in the values for your connection:

    • Name: Enter a name for your connection. For example, VNet1toVNet4.

    • Connection type: Select VNet-to-VNet from the drop-down.

    • First virtual network gateway: This field value is automatically filled in because you're creating this connection from the specified virtual network gateway.

    • Second virtual network gateway: This field is the virtual network gateway of the VNet that you want to create a connection to. Select Choose another virtual network gateway to open the Choose virtual network gateway page.

      • View the virtual network gateways that are listed on this page. Notice that only virtual network gateways that are in your subscription are listed. If you want to connect to a virtual network gateway that isn't in your subscription, use the PowerShell.

      • Select the virtual network gateway to which you want to connect.

      • Shared key (PSK): In this field, enter a shared key for your connection. You can generate or create this key yourself. In a site-to-site connection, the key you use is the same for your on-premises device and your virtual network gateway connection. The concept is similar here, except that rather than connecting to a VPN device, you're connecting to another virtual network gateway.

  4. Select OK to save your changes.

Configure the VNet4 gateway connection

Next, create a connection from VNet4 to VNet1. In the portal, locate the virtual network gateway associated with VNet4. Follow the steps from the previous section, replacing the values to create a connection from VNet4 to VNet1. Make sure that you use the same shared key.

Verify your connections

  1. Locate the virtual network gateway in the Azure portal.

  2. On the Virtual network gateway page, select Connections to view the Connections page for the virtual network gateway. After the connection is established, you'll see the Status values change to Connected.

    Verify connections

  3. Under the Name column, select one of the connections to view more information. When data begins flowing, you'll see values for Data in and Data out.

    Status

Add additional connections

If you want to add additional connections, navigate to the virtual network gateway from which you want to create the connection, then select Connections. You can create another VNet-to-VNet connection, or create an IPsec Site-to-Site connection to an on-premises location. Be sure to adjust the Connection type to match the type of connection you want to create. Before you create additional connections, verify that the address space for your virtual network doesn't overlap with any of the address spaces you want to connect to. For steps to create a Site-to-Site connection, see Create a Site-to-Site connection.

VNet-to-VNet FAQ

View the FAQ details for additional information about VNet-to-VNet connections.

The VNet-to-VNet FAQ applies to VPN gateway connections. For information about VNet peering, see Virtual network peering.

Does Azure charge for traffic between VNets?

VNet-to-VNet traffic within the same region is free for both directions when you use a VPN gateway connection. Cross-region VNet-to-VNet egress traffic is charged with the outbound inter-VNet data transfer rates based on the source regions. For more information, see VPN Gateway pricing page. If you're connecting your VNets by using VNet peering instead of a VPN gateway, see Virtual network pricing.

Does VNet-to-VNet traffic travel across the internet?

No. VNet-to-VNet traffic travels across the Microsoft Azure backbone, not the internet.

Can I establish a VNet-to-VNet connection across Azure Active Directory (AAD) tenants?

Yes, VNet-to-VNet connections that use Azure VPN gateways work across AAD tenants.

Is VNet-to-VNet traffic secure?

Yes, it's protected by IPsec/IKE encryption.

Do I need a VPN device to connect VNets together?

No. Connecting multiple Azure virtual networks together doesn't require a VPN device unless cross-premises connectivity is required.

Do my VNets need to be in the same region?

No. The virtual networks can be in the same or different Azure regions (locations).

If the VNets aren't in the same subscription, do the subscriptions need to be associated with the same Active Directory tenant?

No.

Can I use VNet-to-VNet to connect virtual networks in separate Azure instances?

No. VNet-to-VNet supports connecting virtual networks within the same Azure instance. For example, you can’t create a connection between global Azure and Chinese/German/US government Azure instances. Consider using a Site-to-Site VPN connection for these scenarios.

Can I use VNet-to-VNet along with multi-site connections?

Yes. Virtual network connectivity can be used simultaneously with multi-site VPNs.

How many on-premises sites and virtual networks can one virtual network connect to?

See the Gateway requirements table.

Can I use VNet-to-VNet to connect VMs or cloud services outside of a VNet?

No. VNet-to-VNet supports connecting virtual networks. It doesn't support connecting virtual machines or cloud services that aren't in a virtual network.

Can a cloud service or a load-balancing endpoint span VNets?

No. A cloud service or a load-balancing endpoint can't span across virtual networks, even if they're connected together.

Can I use a PolicyBased VPN type for VNet-to-VNet or Multi-Site connections?

No. VNet-to-VNet and Multi-Site connections require Azure VPN gateways with RouteBased (previously called dynamic routing) VPN types.

Can I connect a VNet with a RouteBased VPN Type to another VNet with a PolicyBased VPN type?

No, both virtual networks MUST use route-based (previously called dynamic routing) VPNs.

Do VPN tunnels share bandwidth?

Yes. All VPN tunnels of the virtual network share the available bandwidth on the Azure VPN gateway and the same VPN gateway uptime SLA in Azure.

Are redundant tunnels supported?

Redundant tunnels between a pair of virtual networks are supported when one virtual network gateway is configured as active-active.

Can I have overlapping address spaces for VNet-to-VNet configurations?

No. You can't have overlapping IP address ranges.

Can there be overlapping address spaces among connected virtual networks and on-premises local sites?

No. You can't have overlapping IP address ranges.

Next steps

For information about how you can limit network traffic to resources in a virtual network, see Network Security.

For information about how Azure routes traffic between Azure, on-premises, and Internet resources, see Virtual network traffic routing.