VNet peering for connectivity in Azure - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is VNet peering in Azure?

VNet peering connects two virtual networks in Azure so they can communicate directly and privately, like connecting two rooms with a door.

intermediate

Can VNets in different regions be peered in Azure?

Yes, Azure supports global VNet peering, allowing VNets in different regions to connect securely and with low latency.

beginner

Does VNet peering require a VPN or gateway?

No, VNet peering connects VNets directly without needing a VPN or gateway, making communication faster and simpler.

intermediate

What is a key limitation of VNet peering regarding overlapping IP address spaces?

VNets with overlapping IP address ranges cannot be peered because the network traffic would be confused about where to send data.

intermediate

How does VNet peering affect network latency and bandwidth?

VNet peering provides low latency and high bandwidth because it uses Azure's backbone network directly without extra hops.

What does VNet peering allow you to do in Azure?

A Create a VPN connection to on-premises network

B Connect two VNets to communicate privately

C Share storage accounts between VNets

D Automatically assign public IPs to VNets

VNet peering connects two VNets so they can communicate privately and directly.

Which of these is NOT required for VNet peering?

A VPN gateway

B Non-overlapping IP address spaces

C Azure subscription

D Virtual networks

VNet peering does not require a VPN gateway; it connects VNets directly.

Can you peer VNets across different Azure regions?

A Only if they share the same subscription

B No, VNets must be in the same region

C Only if they use the same IP range

D Yes, with global VNet peering

Azure supports global VNet peering to connect VNets across regions.

What happens if two VNets have overlapping IP address ranges?

A They cannot be peered

B They peer automatically

C Traffic is routed through VPN

D Azure assigns new IPs automatically

Overlapping IP ranges prevent VNet peering because routing would be ambiguous.

Which network does VNet peering use to connect VNets?

A Third-party VPN service

B Public internet

C Azure backbone network

D Customer's on-premises network

VNet peering uses Azure's private backbone network for fast and secure connectivity.

Explain how VNet peering works and why it is useful for connecting Azure virtual networks.

Think about how two separate rooms can be connected by a door for easy access.

Describe the limitations or conditions that must be met to successfully peer two VNets in Azure.

Consider what might cause confusion in network traffic and what setup steps are needed.

Practice

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

easy

A. To connect two virtual networks for direct communication

B. To create a backup of virtual machines

C. To deploy applications faster

D. To monitor network traffic

Solution

1. Step 1: Understand VNet peering concept

   VNet peering allows two virtual networks to communicate directly without going through the internet.

2. Step 2: Identify the main use case

   This direct communication is the primary purpose, enabling resource sharing securely within Azure.

3. Final Answer:

   To connect two virtual networks for direct communication -> Option A

4. Quick Check:

   VNet peering = direct network connection [OK]

Hint: VNet peering links networks directly, not backups or monitoring [OK]

Common Mistakes:

• Confusing peering with VM backup
• Thinking peering speeds up app deployment
• Assuming peering is for traffic monitoring

2. Which of the following is the correct way to create a VNet peering in Azure Portal?

easy

A. Create a new VNet with peering enabled by default

B. Create peering from one VNet only

C. Create peering from both VNets involved

D. Enable peering in the subscription settings

Solution

1. Step 1: Review peering setup requirements

   VNet peering requires configuration from both virtual networks to allow full communication.

2. Step 2: Identify correct procedure

   Creating peering from both VNets ensures bidirectional connectivity and proper routing.

3. Final Answer:

   Create peering from both VNets involved -> Option C

4. Quick Check:

   Peering setup = both sides configured [OK]

Hint: Peering needs setup on both VNets, not just one [OK]

Common Mistakes:

• Configuring peering only on one VNet
• Assuming peering is automatic on new VNets
• Looking for peering in subscription settings

3. Given two VNets, VNetA and VNetB, peered correctly, what happens when a VM in VNetA tries to ping a VM in VNetB?

medium

A. The ping fails because VNets cannot communicate even if peered

B. The ping fails because peering blocks ICMP traffic

C. The ping succeeds only if both VMs are in the same subnet

D. The ping succeeds because peering allows direct communication

Solution

1. Step 1: Understand VNet peering behavior

   Peering connects VNets so resources can communicate directly, including ping (ICMP) traffic if allowed by NSGs.

2. Step 2: Analyze the ping scenario

   If no network security group blocks ICMP, ping from VM in VNetA to VM in VNetB will succeed due to peering.

3. Final Answer:

   The ping succeeds because peering allows direct communication -> Option D

4. Quick Check:

   Peering enables direct VM communication [OK]

Hint: Peering allows direct traffic unless blocked by security rules [OK]

Common Mistakes:

• Assuming peering blocks ping by default
• Thinking VMs must be in same subnet to communicate
• Believing peering does not enable VNet communication

4. You created VNet peering from VNetA to VNetB but forgot to create peering from VNetB to VNetA. What is the result?

medium

A. Full bidirectional communication between VNets

B. Unidirectional communication from VNetA to VNetB only

C. No communication between VNets

D. Peering automatically completes from both sides

Solution

1. Step 1: Understand peering directionality

   Peering must be created on both VNets for full bidirectional communication.

2. Step 2: Analyze partial peering effect

   With peering only from VNetA to VNetB, traffic flows from A to B but not from B to A.

3. Final Answer:

   Unidirectional communication from VNetA to VNetB only -> Option B

4. Quick Check:

   One-sided peering = one-way traffic [OK]

Hint: Peering one side = one-way connection only [OK]

Common Mistakes:

• Assuming peering is automatic both ways
• Expecting no communication at all
• Thinking peering creates full connection from one side

5. You have two VNets in different Azure regions and want to enable secure, low-latency communication between them. Which VNet peering type should you use?

hard

A. Global VNet peering

B. Local VNet peering

C. VPN Gateway peering

D. ExpressRoute peering

Solution

1. Step 1: Identify peering types and their use cases

   Local VNet peering works within the same region; global VNet peering connects VNets across regions.

2. Step 2: Choose peering for cross-region communication

   Global VNet peering enables secure, low-latency communication between VNets in different Azure regions.

3. Final Answer:

   Global VNet peering -> Option A

4. Quick Check:

   Cross-region VNet peering = global peering [OK]

Hint: Use global peering for cross-region VNet connection [OK]

Common Mistakes:

• Choosing local peering for different regions
• Confusing VPN Gateway with peering
• Selecting ExpressRoute which is for on-premises