VNet-to-VNet connectivity in Azure - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is VNet-to-VNet connectivity in Azure?

VNet-to-VNet connectivity allows two Azure Virtual Networks to connect and communicate securely as if they were on the same network, enabling resources in different VNets to interact.

beginner

Name two common methods to establish VNet-to-VNet connectivity in Azure.

The two common methods are: 1) Using VPN Gateway connections, and 2) Using Azure Virtual Network Peering.

intermediate

What is a key difference between VPN Gateway connection and VNet Peering?

VPN Gateway connections use encrypted tunnels over the internet and can connect VNets across regions or subscriptions, while VNet Peering connects VNets directly within Azure's backbone network with low latency and no encryption overhead.

intermediate

Why might you choose VNet Peering over VPN Gateway for VNet-to-VNet connectivity?

VNet Peering offers faster, lower latency connections with no bandwidth charges and simpler setup when VNets are in the same region or supported cross-region, making it ideal for high-performance needs.

advanced

What is a limitation to keep in mind when using VNet Peering?

VNet Peering requires that the VNets have non-overlapping IP address spaces, and some features like transitive peering (routing through a peered VNet to another VNet) are not supported.

Which Azure service is used to create encrypted tunnels for VNet-to-VNet connectivity?

A Azure Firewall

B VPN Gateway

C Azure Load Balancer

D Azure DNS

VPN Gateway creates encrypted tunnels over the internet to connect VNets securely.

What must be true about IP address ranges when using VNet Peering?

A They must not overlap

B They must be identical

C They must overlap

D They must be public IP ranges

VNet Peering requires non-overlapping IP address spaces to avoid routing conflicts.

Which VNet-to-VNet connectivity option offers lower latency and no bandwidth charges?

A VNet Peering

B VPN Gateway connection

C ExpressRoute

D Azure Bastion

VNet Peering connects VNets directly over Azure's backbone network with low latency and no bandwidth charges.

Can VNet Peering connect VNets across different Azure subscriptions?

A No, only within the same subscription

B Only if they use the same IP range

C Only if they are in the same resource group

D Yes, it supports cross-subscription peering

VNet Peering supports connections across different subscriptions as long as IP ranges do not overlap.

Which method would you use to connect VNets in different Azure regions securely over the internet?

A Azure Load Balancer

B VNet Peering

C VPN Gateway connection

D Azure Traffic Manager

VPN Gateway connections use encrypted tunnels over the internet and support cross-region VNet connectivity.

Explain how VNet-to-VNet connectivity works in Azure and describe the main options available.

Think about how two separate networks can talk to each other securely.

What are the key considerations and limitations when setting up VNet Peering?

Focus on what you must check before peering and what peering cannot do.

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