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Connect Azure Stack Hub to Azure using Azure ExpressRoute

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This article describes how to connect an Azure Stack Hub virtual network to an Azure virtual network using a Microsoft Azure ExpressRoute direct connection.

You can use this article as a tutorial and use the examples to set up the same test environment. Or, you can read the article as a walkthrough that guides you through setting up your own ExpressRoute environment.

Overview, assumptions, and prerequisites

Azure ExpressRoute lets you extend your on-premises networks into the Microsoft cloud over a private connection supplied by a connectivity provider. ExpressRoute is not a VPN connection over the public internet.

For more information about Azure ExpressRoute, see the ExpressRoute overview.

Assumptions

This article assumes that:

  • You have a working knowledge of Azure.
  • You have a basic understanding of Azure Stack Hub.
  • You have a basic understanding of networking.

Prerequisites

To connect Azure Stack Hub and Azure using ExpressRoute, you must meet the following requirements:

  • A provisioned ExpressRoute circuit through a connectivity provider.
  • An Azure subscription to create an ExpressRoute circuit and VNets in Azure.
  • A router that must:
    • Support site-to-site VPN connections between its LAN interface and Azure Stack Hub multi-tenant gateway.
    • Support creating multiple VRFs (Virtual Routing and Forwarding) if there is more than one tenant in your Azure Stack Hub deployment.
  • A router that has:
    • A WAN port connected to the ExpressRoute circuit.
    • A LAN port connected to the Azure Stack Hub multi-tenant gateway.

ExpressRoute network architecture

The following figure shows the Azure Stack Hub and Azure environments after you finish setting up ExpressRoute using the examples in this article:

ExpressRoute network

The following figure shows how multiple tenants connect from the Azure Stack Hub infrastructure through the ExpressRoute router to Azure:

Multi-tenant connections with ExpressRoute

The example in this article uses the same multi-tenant architecture shown in this diagram to connect Azure Stack Hub to Azure using ExpressRoute private peering. The connection is done using a site-to-site VPN connection from the virtual network gateway in Azure Stack Hub to an ExpressRoute router.

The steps in this article show you how to create an end-to-end connection between two VNets from two different tenants in Azure Stack Hub to corresponding VNets in Azure. Setting up two tenants is optional; you can also use these steps for a single tenant.

Configure Azure Stack Hub

To set up the Azure Stack Hub environment for the first tenant, use the following steps as a guide. If you're setting up more than one tenant, repeat these steps:

Note

These steps show how to create resources using the Azure Stack Hub portal, but you can also use PowerShell.

Azure Stack Hub network setup

Before you begin

Before you start configuring Azure Stack Hub, you need:

Create network resources in Azure Stack Hub

Use the following procedures to create the required network resources in Azure Stack Hub for a tenant.

Create the virtual network and VM subnet

  1. Sign in to the Azure Stack Hub user portal.

  2. In the portal, select + Create a resource.

  3. Under Azure Marketplace, select Networking.

  4. Under Featured, select Virtual network.

  5. Under Create virtual network, enter the values shown in the following table into the appropriate fields:

    Field Value
    Name Tenant1VNet1
    Address space 10.1.0.0/16
    Subnet name Tenant1-Sub1
    Subnet address range 10.1.1.0/24

  6. You should see the subscription you created earlier populated in the Subscription field. For the remaining fields:

    • Under Resource group, select Create new to create a new resource group or if you already have one, select Use existing.
    • Verify the default Location.
    • Click Create.
    • (Optional) Click Pin to dashboard.

Create the gateway subnet

  1. Under Virtual network, select Tenant1VNet1.
  2. Under SETTINGS, select Subnets.
  3. Select + Gateway subnet to add a gateway subnet to the virtual network.
  4. The name of the subnet is set to GatewaySubnet by default. Gateway subnets are a special case and must use this name to function correctly.
  5. Verify that the Address range is 10.1.0.0/24.
  6. Click OK to create the gateway subnet.

Create the virtual network gateway

  1. In the Azure Stack Hub user portal, click + Create a resource.
  2. Under Azure Marketplace, select Networking.
  3. Select Virtual network gateway from the list of network resources.
  4. In the Name field, enter GW1.
  5. Select Virtual network.
  6. Select Tenant1VNet1 from the drop-down list.
  7. Select Public IP address, then Choose public IP address, and then click Create new.
  8. In the Name field, type GW1-PiP, and then click OK.
  9. The VPN type should have Route-based selected by default. Keep this setting.
  10. Verify that Subscription and Location are correct. Click Create.

Create the local network gateway

The local network gateway resource identifies the remote gateway at the other end of the VPN connection. For this example, the remote end of the connection is the LAN sub-interface of the ExpressRoute router. For Tenant 1 in the previous diagram, the remote address is 10.60.3.255.

  1. Sign in to the Azure Stack Hub user portal and select + Create a resource.

  2. Under Azure Marketplace, select Networking.

  3. Select local network gateway from the list of resources.

  4. In the Name field, type ER-Router-GW.

  5. For the IP address field, see the previous figure. The IP address of the ExpressRoute router LAN sub-interface for Tenant 1 is 10.60.3.255. For your own environment, enter the IP address of your router's corresponding interface.

  6. In the Address Space field, enter the address space of the VNets that you want to connect to in Azure. The subnets for Tenant 1 are as follows:

    • 192.168.2.0/24 is the hub VNet in Azure.
    • 10.100.0.0/16 is the spoke VNet in Azure.

    Important

    This example assumes that you are using static routes for the site-to-site VPN connection between the Azure Stack Hub gateway and the ExpressRoute router.

  7. Verify that your Subscription, Resource Group, and Location are correct. Then select Create.

Create the connection

  1. In the Azure Stack Hub user portal, select + Create a resource.
  2. Under Azure Marketplace, select Networking.
  3. Select Connection from the list of resources.
  4. Under Basics, choose Site-to-site (IPSec) as the Connection type.
  5. Select the Subscription, Resource group, and Location. Click OK.
  6. Under Settings, select Virtual network gateway, and then select GW1.
  7. Select Local network gateway, and then select ER Router GW.
  8. In the Connection name field, enter ConnectToAzure.
  9. In the Shared key (PSK) field, enter abc123 and then select OK.
  10. Under Summary, select OK.

Get the virtual network gateway public IP address

After you create the virtual network gateway, you can get the gateway's public IP address. Make a note of this address in case you need it later for your deployment. Depending on your deployment, this address is used as the Internal IP address.

  1. In the Azure Stack Hub user portal, select All resources.
  2. Under All resources, select the virtual network gateway, which is GW1 in the example.
  3. Under Virtual network gateway, select Overview from the list of resources. Alternatively, you can select Properties.
  4. The IP address that you want to note is listed under Public IP address. For the example configuration, this address is 192.68.102.1.

Create a virtual machine (VM)

To test data traffic over the VPN connection, you need VMs to send and receive data in the Azure Stack Hub VNet. Create a VM and deploy it to the VM subnet for your virtual network.

  1. In the Azure Stack Hub user portal, select + Create a resource.

  2. Under Azure Marketplace, select Compute.

  3. In the list of VM images, select the Windows Server 2016 Datacenter Eval image.

    Note

    If the image used for this article is not available, ask your Azure Stack Hub operator to provide a different Windows Server image.

  4. In Create virtual machine, select Basics, then type VM01 as the Name.

  5. Enter a valid user name and password. You'll use this account to sign in to the VM after it has been created.

  6. Provide a Subscription, Resource group, and a Location. Select OK.

  7. Under Choose a size, select a VM size for this instance, and then select Select.

  8. Under Settings, confirm that:

    • The virtual network is Tenant1VNet1.
    • The subnet is set to 10.1.1.0/24.

    Use the default settings and click OK.

  9. Under Summary, review the VM configuration and then click OK.

To add more tenants, repeat the steps you followed in these sections:

If you're using Tenant 2 as an example, remember to change the IP addresses to avoid overlaps.

Configure the NAT VM for gateway traversal

Important

This section is for ASDK deployments only. The NAT is not needed for multi-node deployments.

The ASDK is self-contained and isolated from the network where the physical host is deployed. The VIP network that the gateways are connected to is not external; it is hidden behind a router performing Network Address Translation (NAT).

The router is the ASDK host running the Routing and Remote Access Services (RRAS) role. You must configure NAT on the ASDK host to enable the site-to-site VPN connection to connect on both ends.

Configure the NAT

  1. Sign in to the Azure Stack Hub host computer with your admin account.

  2. Run the script in an elevated PowerShell ISE. This script returns your External BGPNAT address.

    Get-NetNatExternalAddress

  3. To configure the NAT, copy and edit the following PowerShell script. Edit the script to replace the External BGPNAT address and Internal IP address with the following example values:

    • For External BGPNAT address use 10.10.0.62
    • For Internal IP address use 192.168.102.1

    Run the following script from an elevated PowerShell ISE:

    $ExtBgpNat = 'External BGPNAT address'
$IntBgpNat = 'Internal IP address'

# Designate the external NAT address for the ports that use the IKE authentication.
Add-NetNatExternalAddress `
   -NatName BGPNAT `
   -IPAddress $Using:ExtBgpNat `
   -PortStart 499 `
   -PortEnd 501
Add-NetNatExternalAddress `
   -NatName BGPNAT `
   -IPAddress $Using:ExtBgpNat `
   -PortStart 4499 `
   -PortEnd 4501
# Create a static NAT mapping to map the external address to the Gateway public IP address to map the ISAKMP port 500 for PHASE 1 of the IPSEC tunnel.
Add-NetNatStaticMapping `
   -NatName BGPNAT `
   -Protocol UDP `
   -ExternalIPAddress $Using:ExtBgpNat `
   -InternalIPAddress $Using:IntBgpNat `
   -ExternalPort 500 `
   -InternalPort 500
# Configure NAT traversal which uses port 4500 to  establish the complete IPSEC tunnel over NAT devices.
Add-NetNatStaticMapping `
   -NatName BGPNAT `
   -Protocol UDP `
   -ExternalIPAddress $Using:ExtBgpNat `
   -InternalIPAddress $Using:IntBgpNat `
   -ExternalPort 4500 `
   -InternalPort 4500

Configure Azure

After you finish configuring Azure Stack Hub, you can deploy the Azure resources. The following figure shows an example of a tenant virtual network in Azure. You can use any name and addressing scheme for your VNet in Azure. However, the address range of the VNets in Azure and Azure Stack Hub must be unique and must not overlap:

Azure VNets

The resources you deploy in Azure are similar to the resources you deployed in Azure Stack Hub. You deploy the following components:

  • Virtual networks and subnets
  • A gateway subnet
  • A virtual network gateway
  • A connection
  • An ExpressRoute circuit

The example Azure network infrastructure is configured as follows:

  • A standard hub (192.168.2.0/24) and spoke (10.100.0.0./16) VNet model. For more information about hub-spoke network topology, see Implement a hub-spoke network topology in Azure.
  • The workloads are deployed in the spoke VNet and the ExpressRoute circuit is connected to the hub VNet.
  • The two VNets are connected using VNet peering.

Configure the Azure VNets

  1. Sign in to the Azure portal with your Azure credentials.
  2. Create the hub VNet using the 192.168.2.0/24 address range.
  3. Create a subnet using the 192.168.2.0/25 address range, and add a gateway subnet using the 192.168.2.128/27 address range.
  4. Create the spoke VNet and subnet using the 10.100.0.0/16 address range.

For more information about creating virtual networks in Azure, see Create a virtual network.

Configure an ExpressRoute circuit

  1. Review the ExpressRoute prerequisites in ExpressRoute prerequisites & checklist.

  2. Follow the steps in Create and modify an ExpressRoute circuit to create an ExpressRoute circuit using your Azure subscription.

    Note

    Give the service key for your circuit to your service so they can set up your ExpressRoute circuit at their end.

  3. Follow the steps in Create and modify peering for an ExpressRoute circuit to configure private peering on the ExpressRoute circuit.

Create the virtual network gateway

Follow the steps in Configure a virtual network gateway for ExpressRoute using PowerShell to create a virtual network gateway for ExpressRoute in the hub VNet.

Create the connection

To link the ExpressRoute circuit to the hub VNet, follow the steps in Connect a virtual network to an ExpressRoute circuit.

Peer the VNets

Peer the hub and spoke VNets using the steps in Create a virtual network peering using the Azure portal. When configuring VNet peering, make sure you use the following options:

  • From the hub to the spoke, Allow gateway transit.
  • From the spoke to the hub, Use remote gateway.

Create a virtual machine

Deploy your workload VMs into the spoke VNet.

Repeat these steps for any additional tenant VNets you want to connect in Azure through their respective ExpressRoute circuits.

Configure the router

You can use the following ExpressRoute router configuration diagram as a guide for configuring your ExpressRoute Router. This figure shows two tenants (Tenant 1 and Tenant 2) with their respective ExpressRoute circuits. Each tenant is linked to their own VRF (Virtual Routing and Forwarding) in the LAN and WAN side of the ExpressRoute router. This configuration ensures end-to-end isolation between the two tenants. Take note of the IP addresses used in the router interfaces as you follow the configuration example.

ExpressRoute router configuration

You can use any router that supports IKEv2 VPN and BGP to terminate the site-to-site VPN connection from Azure Stack Hub. The same router is used to connect to Azure using an ExpressRoute circuit.

The following Cisco ASR 1000 Series Aggregation Services Router configuration example supports the network infrastructure shown in the ExpressRoute router configuration diagram.

ip vrf Tenant 1
 description Routing Domain for PRIVATE peering to Azure for Tenant 1
 rd 1:1
!
ip vrf Tenant 2
 description Routing Domain for PRIVATE peering to Azure for Tenant 2
 rd 1:5
!
crypto ikev2 proposal V2-PROPOSAL2
description IKEv2 proposal for Tenant 1
encryption aes-cbc-256
 integrity sha256
 group 2
crypto ikev2 proposal V4-PROPOSAL2
description IKEv2 proposal for Tenant 2
encryption aes-cbc-256
 integrity sha256
 group 2
!
crypto ikev2 policy V2-POLICY2
description IKEv2 Policy for Tenant 1
match fvrf Tenant 1
 match address local 10.60.3.255
 proposal V2-PROPOSAL2
description IKEv2 Policy for Tenant 2
crypto ikev2 policy V4-POLICY2
 match fvrf Tenant 2
 match address local 10.60.3.251
 proposal V4-PROPOSAL2
!
crypto ikev2 profile V2-PROFILE
description IKEv2 profile for Tenant 1
match fvrf Tenant 1
 match address local 10.60.3.255
 match identity remote any
 authentication remote pre-share key abc123
 authentication local pre-share key abc123
 ivrf Tenant 1
!
crypto ikev2 profile V4-PROFILE
description IKEv2 profile for Tenant 2
 match fvrf Tenant 2
 match address local 10.60.3.251
 match identity remote any
 authentication remote pre-share key abc123
 authentication local pre-share key abc123
 ivrf Tenant 2
!
crypto ipsec transform-set V2-TRANSFORM2 esp-gcm 256
 mode tunnel
crypto ipsec transform-set V4-TRANSFORM2 esp-gcm 256
 mode tunnel
!
crypto ipsec profile V2-PROFILE
 set transform-set V2-TRANSFORM2
 set ikev2-profile V2-PROFILE
!
crypto ipsec profile V4-PROFILE
 set transform-set V4-TRANSFORM2
 set ikev2-profile V4-PROFILE
!
interface Tunnel10
description S2S VPN Tunnel for Tenant 1
 ip vrf forwarding Tenant 1
 ip address 11.0.0.2 255.255.255.252
 ip tcp adjust-mss 1350
 tunnel source TenGigabitEthernet0/1/0.211
 tunnel mode ipsec ipv4
 tunnel destination 10.10.0.62
 tunnel vrf Tenant 1
 tunnel protection ipsec profile V2-PROFILE
!
interface Tunnel20
description S2S VPN Tunnel for Tenant 2
 ip vrf forwarding Tenant 2
 ip address 11.0.0.2 255.255.255.252
 ip tcp adjust-mss 1350
 tunnel source TenGigabitEthernet0/1/0.213
 tunnel mode ipsec ipv4
 tunnel destination 10.10.0.62
 tunnel vrf VNET3
 tunnel protection ipsec profile V4-PROFILE
!
interface GigabitEthernet0/0/1
 description PRIMARY ExpressRoute Link to AZURE over Equinix
 no ip address
 negotiation auto
!
interface GigabitEthernet0/0/1.100
description Primary WAN interface of Tenant 1
 description PRIMARY ER link supporting Tenant 1 to Azure
 encapsulation dot1Q 101
 ip vrf forwarding Tenant 1
 ip address 192.168.1.1 255.255.255.252
!
interface GigabitEthernet0/0/1.102
description Primary WAN interface of Tenant 2
 description PRIMARY ER link supporting Tenant 2 to Azure
 encapsulation dot1Q 102
 ip vrf forwarding Tenant 2
 ip address 192.168.1.17 255.255.255.252
!
interface GigabitEthernet0/0/2
 description BACKUP ExpressRoute Link to AZURE over Equinix
 no ip address
 negotiation auto
!
interface GigabitEthernet0/0/2.100
description Secondary WAN interface of Tenant 1
 description BACKUP ER link supporting Tenant 1 to Azure
 encapsulation dot1Q 101
 ip vrf forwarding Tenant 1
 ip address 192.168.1.5 255.255.255.252
!
interface GigabitEthernet0/0/2.102
description Secondary WAN interface of Tenant 2
description BACKUP ER link supporting Tenant 2 to Azure
 encapsulation dot1Q 102
 ip vrf forwarding Tenant 2
 ip address 192.168.1.21 255.255.255.252
!
interface TenGigabitEthernet0/1/0
 description Downlink to ---Port 1/47
 no ip address
!
interface TenGigabitEthernet0/1/0.211
 description LAN interface of Tenant 1
description Downlink to --- Port 1/47.211
 encapsulation dot1Q 211
 ip vrf forwarding Tenant 1
 ip address 10.60.3.255 255.255.255.254
!
interface TenGigabitEthernet0/1/0.213
description LAN interface of Tenant 2
 description Downlink to --- Port 1/47.213
 encapsulation dot1Q 213
 ip vrf forwarding Tenant 2
 ip address 10.60.3.251 255.255.255.254
!
router bgp 65530
 bgp router-id <removed>
 bgp log-neighbor-changes
 description BGP neighbor config and route advertisement for Tenant 1 VRF
 address-family ipv4 vrf Tenant 1
  network 10.1.0.0 mask 255.255.0.0
  network 10.60.3.254 mask 255.255.255.254
  network 192.168.1.0 mask 255.255.255.252
  network 192.168.1.4 mask 255.255.255.252
  neighbor 10.10.0.62 remote-as 65100
  neighbor 10.10.0.62 description VPN-BGP-PEER-for-Tenant 1
  neighbor 10.10.0.62 ebgp-multihop 5
  neighbor 10.10.0.62 activate
  neighbor 10.60.3.254 remote-as 4232570301
  neighbor 10.60.3.254 description LAN peer for CPEC:INET:2112 VRF
  neighbor 10.60.3.254 activate
  neighbor 10.60.3.254 route-map BLOCK-ALL out
  neighbor 192.168.1.2 remote-as 12076
  neighbor 192.168.1.2 description PRIMARY ER peer for Tenant 1 to Azure
  neighbor 192.168.1.2 ebgp-multihop 5
  neighbor 192.168.1.2 activate
  neighbor 192.168.1.2 soft-reconfiguration inbound
  neighbor 192.168.1.2 route-map Tenant 1-ONLY out
  neighbor 192.168.1.6 remote-as 12076
  neighbor 192.168.1.6 description BACKUP ER peer for Tenant 1 to Azure
  neighbor 192.168.1.6 ebgp-multihop 5
  neighbor 192.168.1.6 activate
  neighbor 192.168.1.6 soft-reconfiguration inbound
  neighbor 192.168.1.6 route-map Tenant 1-ONLY out
  maximum-paths 8
 exit-address-family
 !
description BGP neighbor config and route advertisement for Tenant 2 VRF
address-family ipv4 vrf Tenant 2
  network 10.1.0.0 mask 255.255.0.0
  network 10.60.3.250 mask 255.255.255.254
  network 192.168.1.16 mask 255.255.255.252
  network 192.168.1.20 mask 255.255.255.252
  neighbor 10.10.0.62 remote-as 65300
  neighbor 10.10.0.62 description VPN-BGP-PEER-for-Tenant 2
  neighbor 10.10.0.62 ebgp-multihop 5
  neighbor 10.10.0.62 activate
  neighbor 10.60.3.250 remote-as 4232570301
  neighbor 10.60.3.250 description LAN peer for CPEC:INET:2112 VRF
  neighbor 10.60.3.250 activate
  neighbor 10.60.3.250 route-map BLOCK-ALL out
  neighbor 192.168.1.18 remote-as 12076
  neighbor 192.168.1.18 description PRIMARY ER peer for Tenant 2 to Azure
  neighbor 192.168.1.18 ebgp-multihop 5
  neighbor 192.168.1.18 activate
  neighbor 192.168.1.18 soft-reconfiguration inbound
  neighbor 192.168.1.18 route-map VNET-ONLY out
  neighbor 192.168.1.22 remote-as 12076
  neighbor 192.168.1.22 description BACKUP ER peer for Tenant 2 to Azure
  neighbor 192.168.1.22 ebgp-multihop 5
  neighbor 192.168.1.22 activate
  neighbor 192.168.1.22 soft-reconfiguration inbound
  neighbor 192.168.1.22 route-map VNET-ONLY out
  maximum-paths 8
 exit-address-family
!
ip forward-protocol nd
!
ip as-path access-list 1 permit ^$
ip route vrf Tenant 1 10.1.0.0 255.255.0.0 Tunnel10
ip route vrf Tenant 2 10.1.0.0 255.255.0.0 Tunnel20
!
ip prefix-list BLOCK-ALL seq 5 deny 0.0.0.0/0 le 32
!
route-map BLOCK-ALL permit 10
 match ip address prefix-list BLOCK-ALL
!
route-map VNET-ONLY permit 10
 match as-path 1
!

Test the connection

Test your connection after you establish the site-to-site connection and the ExpressRoute circuit.

Perform the following ping tests:

  • Sign in to one of the VMs in your Azure VNet and ping the VM you created in Azure Stack Hub.
  • Sign in to one of the VMs you created in Azure Stack Hub and ping the VM you created in the Azure VNet.

Note

To make sure you are sending traffic over the site-to-site and ExpressRoute connections, you must ping the dedicated IP (DIP) address of the VM at both ends and not the VIP address of the VM.

Allow ICMP in through the firewall

By default, Windows Server 2016 does not allow incoming ICMP packets through the firewall. For every VM that you use for ping tests, you must allow incoming ICMP packets. To create a firewall rule for ICMP, run the following cmdlet in an elevated PowerShell window:

# Create ICMP firewall rule.
New-NetFirewallRule `
  -DisplayName "Allow ICMPv4-In" `
  -Protocol ICMPv4

Ping the Azure Stack Hub VM

  1. Sign in to the Azure Stack Hub user portal.

  2. Find the VM that you created and select it.

  3. Select Connect.

  4. From an elevated Windows or PowerShell command prompt, enter ipconfig /all. Note the IPv4 address returned in the output.

  5. Ping the IPv4 address from the VM in the Azure VNet.

    In the example environment, the IPv4 address is from the 10.1.1.x/24 subnet. In your environment, the address might be different, but it should be in the subnet you created for the tenant VNet subnet.

View data transfer statistics

If you want to know how much traffic is passing through your connection, you can find this information on the Azure Stack Hub user portal. Viewing data transfer statistics is also a good way to find out whether or not your ping test data went through the VPN and ExpressRoute connections:

  1. Sign in to the Azure Stack Hub user portal and select All resources.
  2. Navigate to the resource group for your VPN Gateway and select the Connection object type.
  3. Select the ConnectToAzure connection from the list.
  4. Under Connections > Overview, you can see statistics for Data in and Data out. You should see some non-zero values.

Next steps

Deploy apps to Azure and Azure Stack Hub