Implement Azure VPN options

Contoso's datacenters support remote connectivity so users can work remotely. Also, some branch offices are connected to the head office datacenter through site-to-site VPNs. As lead system engineer, you must implement a VPN solution that enables ongoing support for the current use scenarios.

VPN gateway design

Using an Azure gateway, you can implement the following various types of VPN connections to address your organizational needs:

  • S2S
  • Multi-site
  • P2S
  • VNet-to-VNet

Site-to-site

You implement an S2S connection over Internet Protocol Security (IPsec)/Internet Key Exchange (IKE). You use S2S connections to support cross-premises and hybrid configurations. To implement an S2S connection, you must have a VPN device with a public IP address, as indicated in the following diagram.

A diagram of a typical S2S VPN configuration. A VNet (IP: 10.10.0.0/16) labelled VNet1 connects via a VPN Gateway device (IP: 131.1.1.) through an IPsec/IKE VPN tunnel to a VPN device (IP: 33.2.1.5) in LocalSite1 at the head office.

Multi-site

A multi-site connection is a variation of the S2S connection. Using this connection type, you create more than one VPN connection from your VNet gateway. When you implement multi-site connections, you must use a RouteBased VPN type.

As the name suggests, you typically use this connection type to connect to multiple on-premises sites, as indicated in the following diagram.

A diagram of a typical multi-site VPN configuration. VNet1 in US West connects through a VPN Gateway (IP: 131.1.1.1). The gateway has two IPsec/IKE VPN tunnels. One connects to LocalSite1(IP: 128.8.8.8), and the other to LocalSite2 (IP: 139.9.9.9).

Tip

A VNet can have only one VPN gateway, so all connections share the bandwidth.

Point-to-site

A P2S VPN connection enables users to connect to your organization from a remote network, such as their home, or a public Wi-Fi hotspot. Users typically initiate P2S connections, as in the following diagram. In the diagram, two users initiate a Secure Socket Tunneling Protocol (SSTP) connection, while a third uses IKEv2. Unlike with S2S connections, you don't need an on-premises public-facing IP address or a VPN device to implement P2S connections.

A diagram of a typical P2S configuration. VNet1 in East US connects to a VPN gateway (IP: 131.1.1.1). Three VPN tunnels are connected inbound to the VPN gateway. Two are of type SSTP while the third is IKEv2. Clients users and devices are displayed on the far side of the tunnel, each with a private IP address allocated from a pool.

Tip

You can use P2S connections together with S2S connections through the same VPN gateway.

VNet-to-VNet

In some ways, implementing VNet-to-VNet connections is similar to connecting a single VNet to an on-premises site location (S2S). In both scenarios, you use a VPN Gateway to implement an IPsec/IKE tunnel.

Note

When you implement a VNet-to-VNet connection through VPN Gateway, the VNets don't need to be in the same Azure region or subscription.

Tip

You can also use peering to connect VNets regardless of the location or subscription. This approach can be faster and more resource efficient.

A diagram of a typical Vnet-to-Vnet connection. VNet1 in East US connects through a VPN Gateway (IP: 131.1.1.1). An IPsec/IKE tunnel connects to a VPN Gateway (IP: 151.2.2.2) which resides on the edge of VNet4, West US region.

ExpressRoute connections

You can use Azure ExpressRoute connections to facilitate a private connection from your on-premises networks to the Microsoft Cloud, or to other sites within your organization. Because the network connection is private, it's more secure, and might also offer significant performance benefits. You configure an ExpressRoute connection by using a VNet gateway. However, with an ExpressRoute connection, you configure the VNet gateway with the gateway type of ExpressRoute, rather than VPN.

Tip

Although traffic travelling over an ExpressRoute circuit is not encrypted by default, you can configure the connection to send encrypted traffic.

It's also possible to combine ExpressRoute and S2S connections, as indicated in the following diagram. For example, you can configure an S2S VPN:

  • As a secure failover path for ExpressRoute.
  • To connect to sites that are not part of your network, but that are connected through ExpressRoute.

A diagram of a dual connection from VNet1, East US, via both an ExpressRoute gateway and a VPN Gateway (IP: 131.1.1.1). The ExpressRoute connection provides private connectivity to On-premises HQ site (IP: 141.4.4.4). The HQ site also has an IPsec/IKE tunnel that connects to VNet1. Finally, VNet1 uses the VPN Gateway to connect to LocalSite2 through an IPsec/IKE tunnel..

Implement VPN gateway

When you configure your VPN gateway, you must select and configure a number of settings. First, you must decide whether to implement a policy-based or route-based configuration.

Policy-based

If you choose to implement policy-based gateways (which are based on static routing), then you must define sets of IP addresses that the gateway uses to determine packet destinations. The gateway evaluates every packet against those sets of IP addresses to determine through which tunnel a packet is encrypted and routed.

Route-based

You can use route-based gateways to avoid the effort of having to define which IP addresses are behind each tunnel. With route-based gateways, IP routing determines across which one of your tunnel interfaces to send each packet.

Tip

You should select route-based VPNs for on-premises devices, because they are more resilient to topology changes—for example, if you create new subnets in your VNet.

You should always choose a route-based VPN gateway for the following types of connectivity:

  • Connections between virtual networks
  • P2S connections
  • Multi-site connections
  • Coexistence with an Azure ExpressRoute gateway

Additional settings

In addition, you must also define the following settings to implement VPN gateway:

  • VPN or ExpressRoute. Choose the fundamental type of connection.
  • Gateway subnet address range. Specifies the private IP address range associated with the VPN gateway.
  • Public IP address. Specifies the public IP address object that gets associated with the VPN gateway.

Create a VNet

To implement a VPN Gateway, you must have a VNet. You can create this before or during the VPN Gateway configuration. We'll create one first. To do this, open the Azure portal and complete the following procedure:

  1. Select Create a resource, and then search for and select Virtual Network.

  2. On the Virtual Network blade, select Create.

  3. Create a VNet by specifying the appropriate properties: Subscription, Resource group, Name, and Region.

    A screenshot of the Create a virtual network page. The administrator has defined the subscription, and selected the ContosoResourceGroup. The VNet name is ContosoVPN1 in the East US region.

  4. Select Next: IP Addresses >.

  5. Configure the subnet that you want to associate with the VNet by either accepting the default settings, or configuring your own.

  6. Select Review + create, and then select Create.

Create the gateway

After you have created the appropriate VNet, you must now create the VPN gateway. For example, to create a route-based VPN gateway using the Azure portal, use the following procedure:

  1. In the Azure portal, search for and select Virtual network gateway.

  2. On the Virtual network gateway blade, select Create.

  3. On the Create virtual network gateway blade, create the gateway by specifying the appropriate properties: Subscription, Name, and Region.

  4. Then choose whether you're implementing a VPN or ExpressRoute connection.

  5. For a VPN, select either Route-based or Policy-based.

    A screenshot of the Create a virtual network gateway page. The administrator has defined the subscription. The Name is ContosoVPNGateway, in the East US region. Gateway type is VPN, and VPN type is Route-based.

  6. Select the virtual network you earlier created.

  7. Configure the Gateway subnet address range and the Public IP address settings.

    A screenshot of the Create a virtual network gateway page. The administrator has selected the Gateway subnet address range (10.3.1.0/24) and has opted to create a new Public IP address called ContosoVPNPublic. Other options are disabled..

  8. Select Review + create, and then select Create.

Try it out

If you would like to work with Azure VPN, then try out these lab exercises. The exercises are based on a sandbox environment, and do not require an Azure subscription to complete: