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Azure VPN Gateway FAQ | Microsoft Docs
The VPN Gateway FAQ. FAQ for Microsoft Azure Virtual Network cross-premises connections, hybrid configuration connections, and VPN Gateways.
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VPN Gateway FAQ

Connecting to virtual networks

Can I connect virtual networks in different Azure regions?

Yes. In fact, there is no region constraint. One virtual network can connect to another virtual network in the same region, or in a different Azure region.

Can I connect virtual networks in different subscriptions?

Yes.

Can I connect to multiple sites from a single virtual network?

You can connect to multiple sites by using Windows PowerShell and the Azure REST APIs. See the Multi-Site and VNet-to-VNet Connectivity FAQ section.

What are my cross-premises connection options?

The following cross-premises connections are supported:

  • Site-to-Site – VPN connection over IPsec (IKE v1 and IKE v2). This type of connection requires a VPN device or RRAS. For more information, see Site-to-Site.
  • Point-to-Site – VPN connection over SSTP (Secure Socket Tunneling Protocol) or IKE v2. This connection does not require a VPN device. For more information, see Point-to-Site.
  • VNet-to-VNet – This type of connection is the same as a Site-to-Site configuration. VNet to VNet is a VPN connection over IPsec (IKE v1 and IKE v2). It does not require a VPN device. For more information, see VNet-to-VNet.
  • Multi-Site – This is a variation of a Site-to-Site configuration that allows you to connect multiple on-premises sites to a virtual network. For more information, see Multi-Site.
  • ExpressRoute – ExpressRoute is a direct connection to Azure from your WAN, not a VPN connection over the public Internet. For more information, see the ExpressRoute Technical Overview and the ExpressRoute FAQ.

For more information about VPN gateway connections, see About VPN Gateway.

What is the difference between a Site-to-Site connection and Point-to-Site?

Site-to-Site (IPsec/IKE VPN tunnel) configurations are between your on-premises location and Azure. This means that you can connect from any of your computers located on your premises to any virtual machine or role instance within your virtual network, depending on how you choose to configure routing and permissions. It's a great option for an always-available cross-premises connection and is well-suited for hybrid configurations. This type of connection relies on an IPsec VPN appliance (hardware device or soft appliance), which must be deployed at the edge of your network. To create this type of connection, you must have an externally facing IPv4 address that is not behind a NAT.

Point-to-Site (VPN over SSTP) configurations let you connect from a single computer from anywhere to anything located in your virtual network. It uses the Windows in-box VPN client. As part of the Point-to-Site configuration, you install a certificate and a VPN client configuration package, which contains the settings that allow your computer to connect to any virtual machine or role instance within the virtual network. It's great when you want to connect to a virtual network, but aren't located on-premises. It's also a good option when you don't have access to VPN hardware or an externally facing IPv4 address, both of which are required for a Site-to-Site connection.

You can configure your virtual network to use both Site-to-Site and Point-to-Site concurrently, as long as you create your Site-to-Site connection using a route-based VPN type for your gateway. Route-based VPN types are called dynamic gateways in the classic deployment model.

Virtual network gateways

Is a VPN gateway a virtual network gateway?

A VPN gateway is a type of virtual network gateway. A VPN gateway sends encrypted traffic between your virtual network and your on-premises location across a public connection. You can also use a VPN gateway to send traffic between virtual networks. When you create a VPN gateway, you use the -GatewayType value 'Vpn'. For more information, see About VPN Gateway configuration settings.

What is a policy-based (static-routing) gateway?

Policy-based gateways implement policy-based VPNs. Policy-based VPNs encrypt and direct packets through IPsec tunnels based on the combinations of address prefixes between your on-premises network and the Azure VNet. The policy (or Traffic Selector) is usually defined as an access list in the VPN configuration.

What is a route-based (dynamic-routing) gateway?

Route-based gateways implement the route-based VPNs. Route-based VPNs use "routes" in the IP forwarding or routing table to direct packets into their corresponding tunnel interfaces. The tunnel interfaces then encrypt or decrypt the packets in and out of the tunnels. The policy or traffic selector for route-based VPNs are configured as any-to-any (or wild cards).

Can I update my Policy-based VPN gateway to Route-based?

No. An Azure Vnet gateway type cannot be changed from policy-based to route-based or the other way. The gateway must be deleted and recreated, a process taking around 60 minutes. The IP address of the gateway will not be preserved nor will the Pre-Shared Key (PSK).

  1. Delete any connections associated with the gateway to be deleted.
  2. Delete the gateway:
  1. Create a new gateway of desired type and complete the VPN setup

Do I need a 'GatewaySubnet'?

Yes. The gateway subnet contains the IP addresses that the virtual network gateway services use. You need to create a gateway subnet for your VNet in order to configure a virtual network gateway. All gateway subnets must be named 'GatewaySubnet' to work properly. Don't name your gateway subnet something else. And don't deploy VMs or anything else to the gateway subnet.

When you create the gateway subnet, you specify the number of IP addresses that the subnet contains. The IP addresses in the gateway subnet are allocated to the gateway service. Some configurations require more IP addresses to be allocated to the gateway services than do others. You want to make sure your gateway subnet contains enough IP addresses to accommodate future growth and possible additional new connection configurations. So, while you can create a gateway subnet as small as /29, we recommend that you create a gateway subnet of /27 or larger (/27, /26, /25 etc.). Look at the requirements for the configuration that you want to create and verify that the gateway subnet you have will meet those requirements.

Can I deploy Virtual Machines or role instances to my gateway subnet?

No.

Can I get my VPN gateway IP address before I create it?

No. You have to create your gateway first to get the IP address. The IP address changes if you delete and recreate your VPN gateway.

Can I request a Static Public IP address for my VPN gateway?

No. Only Dynamic IP address assignment is supported. However, this does not mean that the IP address changes after it has been assigned to your VPN gateway. The only time the VPN gateway IP address changes is when the gateway is deleted and re-created. The VPN gateway public IP address doesn't change across resizing, resetting, or other internal maintenance/upgrades of your VPN gateway.

How does my VPN tunnel get authenticated?

Azure VPN uses PSK (Pre-Shared Key) authentication. We generate a pre-shared key (PSK) when we create the VPN tunnel. You can change the auto-generated PSK to your own with the Set Pre-Shared Key PowerShell cmdlet or REST API.

Can I use the Set Pre-Shared Key API to configure my policy-based (static routing) gateway VPN?

Yes, the Set Pre-Shared Key API and PowerShell cmdlet can be used to configure both Azure policy-based (static) VPNs and route-based (dynamic) routing VPNs.

Can I use other authentication options?

We are limited to using pre-shared keys (PSK) for authentication.

How do I specify which traffic goes through the VPN gateway?

Resource Manager deployment model

  • PowerShell: use "AddressPrefix" to specify traffic for the local network gateway.
  • Azure portal: navigate to the Local network gateway > Configuration > Address space.

Classic deployment model

  • Azure portal: navigate to the classic virtual network > VPN connections > Site-to-site VPN connections > Local site name > Local site > Client address space.

Can I configure Force Tunneling?

Yes. See Configure force tunneling.

Can I set up my own VPN server in Azure and use it to connect to my on-premises network?

Yes, you can deploy your own VPN gateways or servers in Azure either from the Azure Marketplace or creating your own VPN routers. You need to configure user-defined routes in your virtual network to ensure traffic is routed properly between your on-premises networks and your virtual network subnets.

Why are certain ports opened on my VPN gateway?

They are required for Azure infrastructure communication. They are protected (locked down) by Azure certificates. Without proper certificates, external entities, including the customers of those gateways, will not be able to cause any effect on those endpoints.

A VPN gateway is fundamentally a multi-homed device with one NIC tapping into the customer private network, and one NIC facing the public network. Azure infrastructure entities cannot tap into customer private networks for compliance reasons, so they need to utilize public endpoints for infrastructure communication. The public endpoints are periodically scanned by Azure security audit.

More information about gateway types, requirements, and throughput

For more information, see About VPN Gateway configuration settings.

Site-to-Site connections and VPN devices

What should I consider when selecting a VPN device?

We have validated a set of standard Site-to-Site VPN devices in partnership with device vendors. A list of known compatible VPN devices, their corresponding configuration instructions or samples, and device specs can be found in the About VPN devices article. All devices in the device families listed as known compatible should work with Virtual Network. To help configure your VPN device, refer to the device configuration sample or link that corresponds to appropriate device family.

Where can I find VPN device configuration settings?

[!INCLUDE vpn devices]

How do I edit VPN device configuration samples?

For information about editing device configuration samples, see Editing samples.

Where do I find IPsec and IKE parameters?

For IPsec/IKE parameters, see Parameters.

Why does my policy-based VPN tunnel go down when traffic is idle?

This is expected behavior for policy-based (also known as static routing) VPN gateways. When the traffic over the tunnel is idle for more than 5 minutes, the tunnel will be torn down. When traffic starts flowing in either direction, the tunnel will be reestablished immediately.

Can I use software VPNs to connect to Azure?

We support Windows Server 2012 Routing and Remote Access (RRAS) servers for Site-to-Site cross-premises configuration.

Other software VPN solutions should work with our gateway as long as they conform to industry standard IPsec implementations. Contact the vendor of the software for configuration and support instructions.

Point-to-Site using native Azure certificate authentication

This section applies to the Resource Manager deployment model.

[!INCLUDE P2S Azure cert]

Point-to-Site using RADIUS authentication

This section applies to the Resource Manager deployment model.

[!INCLUDE vpn-gateway-point-to-site-faq-include]

VNet-to-VNet and Multi-Site connections

[!INCLUDE vpn-gateway-vnet-vnet-faq-include]

Can I use Azure VPN gateway to transit traffic between my on-premises sites or to another virtual network?

Resource Manager deployment model
Yes. See the BGP section for more information.

Classic deployment model
Transit traffic via Azure VPN gateway is possible using the classic deployment model, but relies on statically defined address spaces in the network configuration file. BGP is not yet supported with Azure Virtual Networks and VPN gateways using the classic deployment model. Without BGP, manually defining transit address spaces is very error prone, and not recommended.

Does Azure generate the same IPsec/IKE pre-shared key for all my VPN connections for the same virtual network?

No, Azure by default generates different pre-shared keys for different VPN connections. However, you can use the Set VPN Gateway Key REST API or PowerShell cmdlet to set the key value you prefer. The key MUST be alphanumerical string of length between 1 to 128 characters.

Do I get more bandwidth with more Site-to-Site VPNs than for a single virtual network?

No, all VPN tunnels, including Point-to-Site VPNs, share the same Azure VPN gateway and the available bandwidth.

Can I configure multiple tunnels between my virtual network and my on-premises site using multi-site VPN?

Yes, but you must configure BGP on both tunnels to the same location.

Can I use Point-to-Site VPNs with my virtual network with multiple VPN tunnels?

Yes, Point-to-Site (P2S) VPNs can be used with the VPN gateways connecting to multiple on-premises sites and other virtual networks.

Can I connect a virtual network with IPsec VPNs to my ExpressRoute circuit?

Yes, this is supported. For more information, see Configure ExpressRoute and Site-to-Site VPN connections that coexist.

IPsec/IKE policy

[!INCLUDE vpn-gateway-ipsecikepolicy-faq-include]

BGP

[!INCLUDE vpn-gateway-faq-bgp-include]

Cross-premises connectivity and VMs

If my virtual machine is in a virtual network and I have a cross-premises connection, how should I connect to the VM?

You have a few options. If you have RDP enabled for your VM, you can connect to your virtual machine by using the private IP address. In that case, you would specify the private IP address and the port that you want to connect to (typically 3389). You'll need to configure the port on your virtual machine for the traffic.

You can also connect to your virtual machine by private IP address from another virtual machine that's located on the same virtual network. You can't RDP to your virtual machine by using the private IP address if you are connecting from a location outside of your virtual network. For example, if you have a Point-to-Site virtual network configured and you don't establish a connection from your computer, you can't connect to the virtual machine by private IP address.

If my virtual machine is in a virtual network with cross-premises connectivity, does all the traffic from my VM go through that connection?

No. Only the traffic that has a destination IP that is contained in the virtual network Local Network IP address ranges that you specified will go through the virtual network gateway. Traffic has a destination IP located within the virtual network stays within the virtual network. Other traffic is sent through the load balancer to the public networks, or if forced tunneling is used, sent through the Azure VPN gateway.

How do I troubleshoot an RDP connection to a VM

[!INCLUDE Troubleshoot VM connection]

Virtual Network FAQ

You view additional virtual network information in the Virtual Network FAQ.

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