VNet-to-VNet connectivity in Azure - Mini Project: Build & Apply

VNet-to-VNet connectivity

📖 Scenario: You are setting up a simple network connection between two virtual networks (VNets) in Azure. This connection allows resources in one VNet to communicate with resources in the other VNet securely and privately.

🎯 Goal: Create two Azure VNets and establish a VNet-to-VNet connection between them using virtual network peering.

📋 What You'll Learn

Create two VNets named VNet1 and VNet2 with specified address spaces

Create virtual network peerings between VNet1 and VNet2

Ensure peering allows traffic to flow both ways

💡 Why This Matters

🌍 Real World

Connecting VNets allows different parts of an application or different teams to communicate securely within Azure without exposing traffic to the internet.

💼 Career

Network engineers and cloud architects often set up VNet peerings to build scalable and secure cloud network architectures.

1

Create two VNets with address spaces

Create two virtual networks named VNet1 and VNet2 with address spaces 10.0.0.0/16 and 10.1.0.0/16 respectively using Azure CLI commands.

Azure

# Create VNet1 and VNet2 with specified address spaces
# Your code here

Hint

Use az network vnet create command with --name and --address-prefix options.

2

Create peering from VNet1 to VNet2

Create a virtual network peering named VNet1ToVNet2 from VNet1 to VNet2 allowing virtual network access using Azure CLI.

Azure

az network vnet create --resource-group MyResourceGroup --name VNet1 --address-prefix 10.0.0.0/16
az network vnet create --resource-group MyResourceGroup --name VNet2 --address-prefix 10.1.0.0/16
# Create peering from VNet1 to VNet2
# Your code here

Hint

Use az network vnet peering create with --vnet-name VNet1 and --remote-vnet VNet2.

3

Create peering from VNet2 to VNet1

Create a virtual network peering named VNet2ToVNet1 from VNet2 to VNet1 allowing virtual network access using Azure CLI.

Azure

az network vnet create --resource-group MyResourceGroup --name VNet1 --address-prefix 10.0.0.0/16
az network vnet create --resource-group MyResourceGroup --name VNet2 --address-prefix 10.1.0.0/16
az network vnet peering create --resource-group MyResourceGroup --name VNet1ToVNet2 --vnet-name VNet1 --remote-vnet VNet2 --allow-vnet-access
# Create peering from VNet2 to VNet1
# Your code here

Hint

Repeat the peering creation but swap --vnet-name and --remote-vnet values.

4

Verify peering connection status

Use Azure CLI to check the peering status of VNet1ToVNet2 and VNet2ToVNet1 to ensure the connection is Connected.

Azure

az network vnet create --resource-group MyResourceGroup --name VNet1 --address-prefix 10.0.0.0/16
az network vnet create --resource-group MyResourceGroup --name VNet2 --address-prefix 10.1.0.0/16
az network vnet peering create --resource-group MyResourceGroup --name VNet1ToVNet2 --vnet-name VNet1 --remote-vnet VNet2 --allow-vnet-access
az network vnet peering create --resource-group MyResourceGroup --name VNet2ToVNet1 --vnet-name VNet2 --remote-vnet VNet1 --allow-vnet-access
# Check peering status
# Your code here

Hint

Use az network vnet peering show with the correct --vnet-name and --name parameters.

Practice

1. What is the main purpose of VNet-to-VNet peering in Azure?

easy

A. To create a backup of a virtual network

B. To securely connect two virtual networks for resource sharing

C. To connect a virtual network to the internet

D. To increase the size of a single virtual network

Solution

1. Step 1: Understand VNet-to-VNet peering concept

   VNet-to-VNet peering connects two virtual networks securely to allow communication.

2. Step 2: Identify the purpose of peering

   It enables resource sharing between VNets without exposing them to the internet.

3. Final Answer:

   To securely connect two virtual networks for resource sharing -> Option B

4. Quick Check:

   VNet peering = secure VNet connection [OK]

Hint: Peering connects VNets securely, not to internet or backup [OK]

Common Mistakes:

• Confusing peering with internet connectivity
• Thinking peering increases VNet size
• Assuming peering creates backups

2. Which of the following is the correct way to establish VNet peering between two VNets in Azure?

easy

A. Create peering from VNet1 to VNet2 only

B. Create peering from VNet2 to VNet1 only

C. Create peering from both VNet1 to VNet2 and VNet2 to VNet1

D. No peering needed, VNets connect automatically

Solution

1. Step 1: Review peering setup requirements

   Peering must be created from both VNets to allow two-way communication.

2. Step 2: Identify correct peering configuration

   Only creating peering one way does not enable full connectivity.

3. Final Answer:

   Create peering from both VNet1 to VNet2 and VNet2 to VNet1 -> Option C

4. Quick Check:

   Two-way peering needed = Create peering from both VNet1 to VNet2 and VNet2 to VNet1 [OK]

Hint: Peering must be two-way for full VNet connectivity [OK]

Common Mistakes:

• Setting peering only one way
• Assuming VNets connect automatically
• Confusing peering with VPN gateways

3. Given two VNets, VNetA and VNetB, with peering configured correctly, what happens if you try to access a VM in VNetB from VNetA?

medium

A. The VM in VNetB is accessible as if on the same network

B. The VM in VNetB is blocked by default firewall rules

C. The VM in VNetB is unreachable without a VPN gateway

D. The VM in VNetB is accessible only via public IP

Solution

1. Step 1: Understand effect of correct VNet peering

   Peering allows VNets to communicate privately as if on the same network.

2. Step 2: Analyze access to VM in peered VNet

   VMs can be accessed using private IPs without VPN or public IP.

3. Final Answer:

   The VM in VNetB is accessible as if on the same network -> Option A

4. Quick Check:

   Peering enables private access = The VM in VNetB is accessible as if on the same network [OK]

Hint: Peered VNets act like one network for VM access [OK]

Common Mistakes:

• Thinking VPN gateway is always needed
• Assuming public IP is required
• Confusing firewall rules with peering

4. You set up VNet peering from VNet1 to VNet2 but cannot access resources in VNet2 from VNet1. What is the most likely cause?

medium

A. Peering was not created from VNet2 to VNet1

B. VNet1 and VNet2 have overlapping IP address ranges

C. Network Security Groups block traffic between VNets

D. All of the above

Solution

1. Step 1: Check peering configuration

   Peering must be created both ways; missing one side blocks communication.

2. Step 2: Verify IP address ranges and security rules

   Overlapping IPs cause routing conflicts; NSGs may block traffic.

3. Step 3: Combine all issues

   Any of these can cause access failure; all are common mistakes.

4. Final Answer:

   All of the above -> Option D

5. Quick Check:

   Multiple causes block access = All of the above [OK]

Hint: Check peering, IP ranges, and NSGs when access fails [OK]

Common Mistakes:

• Ignoring one-way peering setup
• Overlapping IP ranges unnoticed
• Not checking firewall or NSG rules

5. You have two VNets in different Azure regions that need to communicate privately. Which approach is best to enable this with minimal latency and no internet exposure?

hard

A. Use VNet-to-VNet peering with global peering enabled

B. Set up a VPN gateway connection between the VNets

C. Connect VNets via public IP addresses

D. Use ExpressRoute with public peering

Solution

1. Step 1: Identify connectivity options for cross-region VNets

   Global VNet peering allows private, low-latency connection between VNets in different regions.

2. Step 2: Compare alternatives

   VPN gateways add latency and complexity; public IPs expose traffic; ExpressRoute public peering is not private.

3. Step 3: Choose best practice

   Global VNet peering is recommended for private, fast cross-region VNet communication.

4. Final Answer:

   Use VNet-to-VNet peering with global peering enabled -> Option A

5. Quick Check:

   Global peering = private, low latency cross-region [OK]

Hint: Global peering connects regions privately with low latency [OK]

Common Mistakes:

• Using VPN gateways unnecessarily
• Exposing traffic via public IPs
• Confusing ExpressRoute public peering with private