3-vwan-sec-single-region

Secured Virtual WAN - Single Region

Lab: Vwan23

Contents

• Overview
• Prerequisites
• Deploy the Lab
• Troubleshooting
• Testing
  • 1. Ping IP
  • 2. Ping DNS
  • 3. Curl DNS
  • 4. Private Link Service
  • 5. Azure Firewall
  • 6. Virtual WAN Routes
  • 7. Onprem Routes
• Cleanup

Overview

This terraform code deploys a single-region Secured Virtual WAN (Vwan) testbed to observe traffic routing patterns. Routing Intent feature is enabled to allow traffic inspection on Azure firewalls for traffic between spokes and branches.

Standard Virtual Network (Vnet) hub (Hub1) connects to the Vwan hub (vHub1) via a Vwan connection. Direct spoke (Spoke1) is connected to the Vwan hub (vHub1). Spoke2is an indirect spoke from a Vwan perspective; and is connected via standard Vnet peering to Hub1. Spoke2 uses the Network Virtual Applinace (NVA) in the standard Vnet hub (Hub1) as the next hop for traffic to all destinations.

The isolated spoke (Spoke3) does not have Vnet peering to the Vnet hub (Hub1), but is reachable via Private Link Service through a private endpoint in the hub.

Branch1 is an on-premises network which is simulated using Vnet. Multi-NIC Cisco-CSR-1000V NVA appliances connect to the Vwan hubs using IPsec VPN connections with dynamic (BGP) routing.

Prerequisites

Ensure you meet all requirements in the prerequisites before proceeding.

Deploy the Lab

1. Clone the Git Repository for the Labs

git clone https://github.com/kaysalawu/azure-network-terraform.git

2. Navigate to the lab directory

cd azure-network-terraform/2-virtual-wan/3-vwan-sec-single-region

3. Run the following terraform commands and type yes at the prompt:

terraform init
terraform plan
terraform apply

Troubleshooting

See the troubleshooting section for tips on how to resolve common issues that may occur during the deployment of the lab.

Testing

Each virtual machine is pre-configured with a shell script to run various types of tests. Serial console access has been configured for all virtual mchines. You can access the serial console of a virtual machine from the Azure portal.

Login to virtual machine Vwan23-spoke1-vm via the serial console.

• username = azureuser
• password = Password123

Run the following tests from inside the serial console.

1. Ping IP

This script pings the IP addresses of some test virtual machines and reports reachability and round trip time.

Run the IP ping test

ping-ip

Sample output

azureuser@Vwan23-spoke1-vm:~$ ping-ip

 ping ip ...

branch1 - 10.10.0.5 -OK 7.047 ms
hub1    - 10.11.0.5 -OK 4.225 ms
spoke1  - 10.1.0.5 -OK 0.033 ms
spoke2  - 10.2.0.5 -OK 7.836 ms
internet - icanhazip.com -NA

2. Ping DNS

This script pings the DNS name of some test virtual machines and reports reachability and round trip time.

Run the DNS ping test

ping-dns

Sample output

azureuser@Vwan23-spoke1-vm:~$ ping-dns

 ping dns ...

vm.branch1.corp - 10.10.0.5 -OK 11.077 ms
vm.hub1.az.corp - 10.11.0.5 -OK 4.083 ms
vm.spoke1.az.corp - 10.1.0.5 -OK 0.040 ms
vm.spoke2.az.corp - 10.2.0.5 -OK 5.036 ms
icanhazip.com - 104.18.114.97 -NA

3. Curl DNS

This script uses curl to check reachability of web server (python Flask) on the test virtual machines. It reports HTTP response message, round trip time and IP address.

Run the DNS curl test

curl-dns

Sample output

azureuser@Vwan23-spoke1-vm:~$ curl-dns

 curl dns ...

200 (0.033560s) - 10.10.0.5 - vm.branch1.corp
200 (0.024494s) - 10.11.0.5 - vm.hub1.az.corp
200 (0.023244s) - 10.11.4.4 - pep.hub1.az.corp
[10076.943032] cloud-init[1519]: 10.1.0.5 - - [17/Sep/2023 11:55:14] "GET / HTTP/1.1" 200 -
200 (0.017153s) - 10.1.0.5 - vm.spoke1.az.corp
200 (0.024705s) - 10.2.0.5 - vm.spoke2.az.corp
000 (2.001853s) -  - vm.spoke3.az.corp
200 (0.036730s) - 104.18.114.97 - icanhazip.com

We can see that spoke3 vm.spoke3.az.corp returns a 000 HTTP response code. This is expected as there is no Vnet peering to Spoke3 from Hub1. But Spoke3 web application is reachable via Private Link Service private endpoint pep.hub1.az.corp.

4. Private Link Service

Test access to Spoke3 application using the private endpoint in Hub1.

curl pep.hub1.az.corp

Sample output

azureuser@Vwan23-spoke1-vm:~$ curl pep.hub1.az.corp
{
  "headers": {
    "Accept": "*/*",
    "Host": "pep.hub1.az.corp",
    "User-Agent": "curl/7.68.0"
  },
  "hostname": "Vwan23-spoke3-vm",
  "local-ip": "10.3.0.5",
  "remote-ip": "10.3.3.4"
}

Sample output

The hostname and local-ip fields belong to the servers running the web application - in this case Spoke3 virtual machine. The remote-ip field (as seen by the web servers) is an IP addresses in the Private Link Service NAT subnet.

5. Azure Firewall

1. Run a tracepath vm.spoke2.az.corp (10.2.0.5) to observe the traffic flow through the Azure Firewall.

tracepath vm.spoke2.az.corp

Sample output

azureuser@Vwan23-spoke1-vm:~$ tracepath 10.2.0.5
 1?: [LOCALHOST]                      pmtu 1500
 1:  192.168.11.166                                        3.633ms
 1:  192.168.11.165                                        2.666ms
 2:  10.11.1.9                                             6.408ms
 3:  10.2.0.5                                              6.318ms reached
     Resume: pmtu 1500 hops 3 back 3

We can observe that the traffic flow from Spoke1 to Spoke2 goes through the Azure Firewall in Hub1 (192.168.11.166 and 192.168.11.165 in this example). Traffic then flows via the Network Virtual Appliance (NVA) in Hub1 (10.11.1.9) before reaching the destination - Spoke2 (10.2.0.5).

2. Check the Azure Firewall logs to observe the traffic flow.

• Select the Azure Firewall resource Vwan23-azfw-hub1 in the Azure portal.
• Click on Logs in the left navigation pane.
• Click Run in the Network rule log data log category.

• On the TargetIP column deselect all IP addresses except spoke2 (10.2.0.5)

Observe how traffic from spoke1 (10.1.0.5) to spoke2 flows via the firewall as expected.

Repeat steps 1-5 for all other spoke and branch virtual machines.

6. Virtual WAN Routes

1. Ensure you are in the lab directory azure-network-terraform/2-virtual-wan/3-vwan-sec-single-region
2. Display the virtual WAN routing table(s)

bash ../../scripts/_routes.sh Vwan23RG

Sample output

3-vwan-sec-single-region$ bash ../../scripts/_routes.sh Vwan23RG

Resource group: Vwan23RG

vHUB: Vwan23-vhub1-hub
Effective route table: defaultRouteTable
AddressPrefixes    NextHopType                 AsPath
-----------------  --------------------------  --------
10.11.0.0/16       Virtual Network Connection
10.1.0.0/16        Virtual Network Connection
10.2.0.0/16        HubBgpConnection            65010
10.10.0.0/24       VPN_S2S_Gateway             65001

7. Onprem Routes

Let's login to the onprem router Vwan23-branch1-nva and observe its dynamic routes.

1. Login to virtual machine Vwan23-branch1-nva via the serial console.
2. Enter username and password
   • username = azureuser
   • password = Password123
3. Enter the Cisco enable mode

enable

4. Display the routing table

show ip route

Sample output

Vwan23-branch1-nva-vm#show ip route
...
[Truncated for brevity]
...
Gateway of last resort is 10.10.1.1 to network 0.0.0.0

S*    0.0.0.0/0 [1/0] via 10.10.1.1
      10.0.0.0/8 is variably subnetted, 12 subnets, 4 masks
B        10.1.0.0/16 [20/0] via 192.168.11.12, 02:49:25
B        10.2.0.0/16 [20/0] via 192.168.11.12, 02:49:25
S        10.10.0.0/24 [1/0] via 10.10.2.1
C        10.10.1.0/24 is directly connected, GigabitEthernet1
L        10.10.1.9/32 is directly connected, GigabitEthernet1
C        10.10.2.0/24 is directly connected, GigabitEthernet2
L        10.10.2.9/32 is directly connected, GigabitEthernet2
C        10.10.10.0/30 is directly connected, Tunnel0
L        10.10.10.1/32 is directly connected, Tunnel0
C        10.10.10.4/30 is directly connected, Tunnel1
L        10.10.10.5/32 is directly connected, Tunnel1
B        10.11.0.0/16 [20/0] via 192.168.11.12, 02:49:25
      168.63.0.0/32 is subnetted, 1 subnets
S        168.63.129.16 [254/0] via 10.10.1.1
      169.254.0.0/32 is subnetted, 1 subnets
S        169.254.169.254 [254/0] via 10.10.1.1
      192.168.10.0/32 is subnetted, 1 subnets
C        192.168.10.10 is directly connected, Loopback0
      192.168.11.0/24 is variably subnetted, 3 subnets, 2 masks
B        192.168.11.0/24 [20/0] via 192.168.11.12, 02:49:25
S        192.168.11.12/32 is directly connected, Tunnel1
S        192.168.11.13/32 is directly connected, Tunnel0

5. Display BGP information

show ip bgp

Sample output

Vwan23-branch1-nva-vm#show ip bgp
BGP table version is 7, local router ID is 192.168.10.10
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
              x best-external, a additional-path, c RIB-compressed,
              t secondary path, L long-lived-stale,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
 r    0.0.0.0          192.168.11.12                          0 65515 i
 r>                    192.168.11.13                          0 65515 i
 *    10.1.0.0/16      192.168.11.13                          0 65515 i
 *>                    192.168.11.12                          0 65515 i
 *    10.2.0.0/16      192.168.11.13            0             0 65515 65010 i
 *>                    192.168.11.12            0             0 65515 65010 i
 *>   10.10.0.0/24     10.10.2.1                0         32768 i
 *    10.11.0.0/16     192.168.11.13                          0 65515 i
 *>                    192.168.11.12                          0 65515 i
 *    192.168.11.0     192.168.11.13                          0 65515 i
 *>                    192.168.11.12                          0 65515 i

Cleanup

1. Make sure you are in the lab directory

cd azure-network-terraform/2-virtual-wan/3-vwan-sec-single-region

2. Delete the resource group to remove all resources installed.
   Run the following Azure CLI command:

az group delete -g Vwan23RG --no-wait