Azure Networking

Virtual networks, VPN, and connectivity

Virtual Networks (VNets)

Azure Virtual Networks provide isolated network environments for your resources.

Key Concepts

* Address Space: CIDR blocks defining the VNet IP range (e.g., 10.0.0.0/16)
* Subnets: Subdivisions within a VNet for resource organization
* Peering: Connecting VNets for cross-network communication
* Service Endpoints: Direct connectivity to Azure services

Best Practices

* Plan IP address space to avoid overlaps with on-premises networks
* Use Network Security Groups (NSGs) on all subnets
* Enable VNet flow logs for troubleshooting
* Consider Hub-Spoke topology for multi-VNet architectures

VPN Gateway

Azure VPN Gateway enables secure site-to-site and point-to-site connectivity.

Connection Types

Type	Use Case
Site-to-Site (S2S)	Connect on-premises to Azure via IPsec tunnel
Point-to-Site (P2S)	Individual client connections (remote users)
VNet-to-VNet	Connect Azure VNets across regions

SKU Selection

* Basic: Development/test only (being retired)
* VpnGw1-3: Production workloads with varying throughput
* VpnGw1-5AZ: Zone-redundant for high availability

Network Security Groups

NSGs filter network traffic to and from Azure resources.

Rule Components

* Priority: 100-4096, lower numbers processed first
* Source/Destination: IP, service tag, or ASG
* Protocol: TCP, UDP, ICMP, or Any
* Action: Allow or Deny

Tip: Use Application Security Groups (ASGs) to group VMs logically instead of managing individual IP addresses.