Azure Learning

Manage and Control Traffic Flow with Routes

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tagsaz-104, networking, routing, udr, nva

2 min read

Module 4 · Manage & Control Traffic Flow with Routes

MS Learn: Manage and control traffic flow in your Azure deployment with routes · learn.control-network-traffic-flow-with-routes Module note for Path MOC

Overview

Steer where traffic actually goes. Azure provides automatic system routes; this module shows how to override them with user-defined routes (UDRs) and deploy a network virtual appliance (NVA) — a VM acting as a firewall/router — to inspect or force traffic through a chosen path.

Learning objectives (from Microsoft Learn)

In this module, you will:

  • Identify the routing capabilities of an Azure virtual network.
  • Configure routing within a virtual network.
  • Deploy a basic network virtual appliance.
  • Configure routing to send traffic through a network virtual appliance.

Units

  1. Introduction
  2. Azure Virtual Network route tables
  3. Exercise: create custom (user-defined) routes
  4. Network virtual appliances (NVAs)
  5. Exercise: create an NVA VM
  6. Exercise: route traffic through the NVA
  7. Summary

Concepts introduced

  • Route tables & UDRs — override system routes at the subnet level.
  • BGP — dynamic route exchange for hybrid connectivity (contrast to static UDRs).
  • Azure Firewall — the managed alternative to a self-run NVA.
  • VNet / subnet — the scope where routes apply.

Key terms & commands (Azure CLI)

az network route-table create -g <rg> -n rt-none
az network route-table route create -g <rg> --route-table-name rt-none -n to-internet     --address-prefix 0.0.0.0/0 --next-hop-type Internet
az network vnet subnet update -g <rg> --vnet-name <vnet> -n snet-app --route-table rt-none

Hands-on

  • Create a route table, add a UDR, associate to a subnet, and use Network Watcher → Next Hop to confirm the applied next hop.
  • Deploy an NVA VM, add a UDR pointing 0.0.0.0/0 (or specific prefix) at the NVA’s IP, and verify traffic is steered through it.

Exam focus

  • Precedence: UDR > BGP > system; longest-prefix-match always wins.
  • A route table does nothing until associated to a subnet.
  • Next hop types: VirtualNetwork, Internet, VirtualAppliance, VirtualNetworkGateway, None, VNet peering.
  • UDR + peer = service chaining (hub-and-spoke routing).

Path MOC · route-table · azure-firewall · bgp · vnet · subnet

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