Azure Virtual Network Peering
By Pooja | 18th July 2025
Introduction
As cloud environments scale, the ability to securely connect and manage multiple network segments across geographies becomes essential. While Azure Virtual Network (VNet) offers isolated networking environments for your resources, there’s often a need to connect these VNets—either for application integration, data replication, or centralized management.
This is where Azure VNet Peering comes into play. It allows seamless and private communication between VNets—whether within the same region (Local Peering) or across Azure regions (Global Peering).
This article provides a deep dive into VNet Peering, comparing local and global peering, explaining use cases, configuration details, and best practices to ensure secure, scalable, and efficient cloud networking.
What is Azure Virtual Network Peering?
Azure Virtual Network Peering is a mechanism that allows you to connect two or more VNets so they appear as a single network. Once peered, virtual machines and other resources in these networks can communicate with each other using private IP addresses—without the need for public IPs, VPN tunnels, or gateways.
Key characteristics of VNet Peering:
- Low latency and high bandwidth
- Private and secure
- No need for public IPs or NAT
- No gateway required
Why Use VNet Peering?
Some key reasons to implement VNet peering include:
- Application tier separation (e.g., app layer in one VNet, database in another)
- Business unit isolation with controlled communication
- Region-based architecture (e.g., East US frontend and West US backend)
- Centralized services such as logging, DNS, or firewalls
- Mergers or acquisitions requiring inter-network communication
Peering enables flexibility in design while maintaining security, control, and performance.
Types of VNet Peering
- Local VNet Peering
Local Peering connects two VNets within the same Azure region.
Example: Connect a web server VNet and a database VNet in East US to maintain modular design.
- Global VNet Peering
Global Peering connects VNets across different Azure regions.
Example: Connect a VNet in East US to one in West Europe for global app architecture or backup redundancy.
How VNet Peering Works
When two VNets are peered:
- A bidirectional connection is established (each VNet must be configured)
- Azure updates route tables to allow communication
- Private IP addresses are used across peered VNets
- Traffic remains on Microsoft’s backbone (no public internet involved)
You can control access using:
- Network Security Groups (NSGs)
- Route filters
- Service endpoints and Private Link
Comparison: Local vs Global Peering
Feature | Local VNet Peering | Global VNet Peering |
Region | Same region | Different regions |
Latency | Lower | Slightly higher |
Cost | Lower (intra-region rate) | Higher (inter-region egress) |
Gateway Required | No | No |
Traffic Path | Azure Backbone | Azure Global Backbone |
Use Cases | App-data tiers, microservices | DR, global applications |
VNet Peering vs VPN Gateway vs ExpressRoute
Feature | VNet Peering | VPN Gateway | ExpressRoute |
Latency | Low | Moderate (over internet) | Very low (private connection) |
Security | High (no public IPs) | Encrypted over public internet | Very high (private fiber) |
Cost | Lower | Pay per connection + bandwidth | High initial + usage fee |
Throughput | High (depends on VM SKU) | Limited by gateway SKU | Very high (10 Gbps +) |
Setup Complexity | Simple | Moderate | Complex |
Use VNet Peering for internal communication; VPN for hybrid setups; and ExpressRoute for critical, high-throughput, on-prem connectivity.
Key Configuration Considerations
To configure VNet Peering, both networks must:
- Not have overlapping address spaces
- Belong to the same Azure AD tenant (for most use cases)
- Allow traffic forwarding if required (e.g., via firewall)
- Enable network access in the peering settings
Example using Azure CLI:
bash
CopyEdit
az network vnet peering create \
 –name EastToWestPeering \
 –resource-group MyRG \
 –vnet-name EastVNet \
 –remote-vnet /subscriptions/{sub-id}/resourceGroups/MyRG/providers/Microsoft.Network/virtualNetworks/WestVNet \
 –allow-vnet-access
Security and Access Control in Peering
- NSGs can restrict access even in peered VNets
- Peering settings can:
- Allow/disallow forwarded traffic
- Use remote gateways
- Allow access to linked services
- Logging via Azure Monitor or Network Watcher to audit peering activity
You should always:
- Restrict traffic using NSGs
- Enable diagnostic logs
- Validate routes via Effective Routes in NIC properties
Common Use Cases
- Multi-tier Applications
App, web, and database tiers are separated into VNets and peered for better control and security.
- Cross-Region Replication
Global peering allows database replication between regions for disaster recovery.
- Shared Services VNet
Central DNS, firewall, logging, and management tools are placed in one VNet and shared across others.
- M&A Integration
Businesses acquiring another company can peer their VNets to unify systems securely.
- Dev/Test Isolation
Developers work in isolated VNets that are peered with core systems for controlled access.
Pricing and Cost Implications
Local Peering Cost
- Data Transfer: Inbound is free, outbound is billed at intra-region rate (low cost)
Global Peering Cost
- Charged based on inter-region egress rates, which vary by region
For example:
- East US to West Europe may have higher rates than East US to Central US
Limitations and Quotas
- A VNet can have up to 500 peering connections
- Peering cannot happen between overlapping address spaces
- No transitive peering (VNetA ↔ VNetB ↔ VNetC ≠A↔C)
- Global peering supports only Azure Resource Manager (ARM) VNets
- Some services (e.g., Azure Bastion, AKS) require additional configuration
Best Practices for VNet Peering
- Avoid overlapping address spaces at planning stage
- Use naming conventions to keep track of peering connections
- Enable “use remote gateway” only when necessary
- Secure traffic with NSGs, ASGs, or Azure Firewall
- Audit and monitor peering logs regularly
- Use Bicep or Terraform to manage large-scale peering consistently
- Always test peering in a non-prod environment first
Real-World Scenario Example
Scenario: A company has:
- Web Frontend VNet in East US
- Backend API VNet in West US
- Shared Services VNet in Central US
Using Global Peering, they can:
- Enable communication between frontend and backend
- Allow all VNets to connect to shared DNS, Azure Firewall, and monitoring tools
- Maintain segregation of duties and workloads while simplifying connectivity
Conclusion
Azure VNet Peering is a foundational feature for building secure, high-performance, and flexible network architectures in the cloud. It enables private connectivity across VNets—either in the same region (local peering) or across different regions (global peering)—without requiring complex setups or additional hardware.
Whether you’re designing microservices, implementing a global backup strategy, or integrating enterprise networks after a merger, VNet Peering provides the simplicity, speed, and security needed for success.
Understanding how to configure, secure, and manage peering connections is essential for every cloud architect and Azure administrator. With proper planning, you can ensure seamless communication across your entire Azure network footprint, driving business continuity and cloud agility.
Introduction
In cloud computing, backup and replication are fundamental to system reliability, disaster recovery, and scalability. Microsoft Azure offers two essential tools that help achieve these goals: Snapshots and Images.
Whether you’re trying to preserve the current state of a virtual machine (VM), automate mass deployments, or recover quickly from failure, Azure Images and Snapshots allow you to capture, reuse, and replicate VM disk states efficiently.
In this article, we’ll explore the concepts, differences, use cases, implementation strategies, and best practices for using Azure Snapshots and Images effectively in your cloud infrastructure.
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