Azure Networking
What This Chapter Is About
Turn Azure organization and governance boundaries into a practical networking model.
This chapter helps readers understand how Azure systems connect safely across applications, environments, platform services, Azure services, and on-premises networks. The focus is not to memorize networking features. The focus is to understand how connectivity, segmentation, routing, private access, and hybrid connectivity shape architecture decisions.
Keep one durable idea in view:
Azure networking is the design of intentional paths: who can reach what, over which route, through which controls, and whether access should be public, private, hybrid, or isolated.
Sections
How the Chapter Develops
The chapter develops in this order:
Continue from governance by showing that cloud boundaries still need intentional communication paths.
Define networking as a set of practical questions about connectivity, isolation, routing, inspection, private access, and hybrid reachability.
Introduce virtual networks and subnets as the basic private network placement model in Azure.
Explain network security groups as traffic filtering controls used for segmentation and least-allowed communication.
Explain route tables as the control for shaping traffic paths through platform services, firewalls, appliances, or hybrid networks.
Show how VNet peering supports hub-spoke design, shared connectivity, and workload separation.
Compare hybrid connectivity choices, especially ExpressRoute and VPN, through reliability, privacy, cost, and migration needs.
Explain private endpoints as a way to reach Azure platform services through private IP addresses, with DNS as part of the design.
Apply the model to a hybrid enterprise migration where workloads need segmentation, private service access, hybrid connectivity, and controlled routing.
Together, these sections show that networking is not only about allowing traffic. It is about making communication paths explicit enough to secure, operate, troubleshoot, and evolve.
What You Will Be Able to Do
By the end of this chapter, the reader should be able to:
Explain Azure networking in plain language.
Describe the role of virtual networks, subnets, network security groups, route tables, VNet peering, ExpressRoute, VPN, and private endpoints.
Decide when workloads should share a network, use separate networks, or connect through hub-spoke design.
Explain how segmentation reduces blast radius and supports different application tiers or environments.
Describe how routing decisions affect security inspection, hybrid connectivity, and operational troubleshooting.
Compare ExpressRoute and VPN at a high level for hybrid connectivity.
Explain why private endpoints often require DNS design, not only network configuration.
Sketch a networking model for a hybrid enterprise migration.
Key Ideas
Networking defines intentional communication paths between users, workloads, Azure services, platform services, and on-premises systems.
A virtual network is a private network boundary in Azure, and subnets divide that boundary into smaller placement and control areas.
IP address planning matters because overlapping address spaces can block peering, routing, and migration options.
Network security groups filter traffic and help enforce segmentation, but they are not a full application security model by themselves.
Route tables influence where traffic goes, including through firewalls, appliances, gateways, or hybrid connections.
VNet peering connects virtual networks and supports hub-spoke architecture when shared services should be centralized.
ExpressRoute and VPN both connect Azure to external networks, but they differ in privacy, reliability, cost, and operating model.
Private endpoints let workloads reach supported Azure services through private IP addresses, which changes both network and DNS design.
Strong networking design balances connectivity and isolation.