Lab 19 – Network Monitoring Tools (Network Watcher)

Objectives

Prerequisites

Estimated time

35 minutes

Part 1 – Enable Network Watcher

Network Watcher is typically auto-enabled per region when you create networking

resources. To verify/enable:

  1. Search for Network Watcher > check the region (e.g., East US) is

listed and Status is Enabled.

  1. If not, select the region > Enable (or select Configure on an

existing region).

Part 2 – Setup VMs (if not reusing prior labs)

  1. Search for Resource groups > Create. Name: rg-az104-lab19,

region: East US. Create.

  1. Virtual networks > Create. Name: vnet-lab19, Address space:

10.100.0.0/16, Subnets: subnet-vms with 10.100.1.0/24. Create.

  1. Create two VMs:

- vm-source: Ubuntu 22.04 LTS, Standard_B1s, vnet-lab19/subnet-vms

with a public IP. Create.

- vm-dest: same config, but with no public IP. Create.

Part 3 – Connection Troubleshoot

ℹ️

tip

Connection Troubleshoot is faster and less intrusive than IP Flow Verify for initial connectivity diagnosis. Use it first, then drill down with other tools if needed.

  1. Go to Network Watcher > Connection troubleshoot (under Network

diagnostic tools).

  1. Source:

- Resource type: Virtual machine

- Virtual machine: vm-source

- Network interface: (auto-selected)

  1. Destination:

- Resource type: Virtual machine

- Virtual machine: vm-dest

- Port: 22

  1. Check — Network Watcher tests connectivity and reports latency, hops,

and success/failure. Useful for diagnosing "VM A can't reach VM B" scenarios.

Part 4 – IP flow verify

  1. Network Watcher > IP flow verify (under Network diagnostic tools).
  2. VM: vm-source
  3. Network interface: (auto-selected)
  4. Direction: Outbound
  5. Protocol: TCP
  6. Local IP address/port: 10.100.1.4:* (or the VM's actual private IP)
  7. Remote IP address/port: 10.100.1.5:22 (or vm-dest's private IP)
  8. Check — should show Allow if no NSG rules block it. Try with port 3389

(RDP) or a blocked port to see Deny.

Part 5 – Next hop

  1. Network Watcher > Next hop (under Network diagnostic tools).
  2. VM: vm-source
  3. Network interface: (auto-selected)
  4. Source IP address: 10.100.1.4 (or the VM's private IP)
  5. Destination IP address: 10.100.1.5 (or a destination within the VNet)
  6. Check — should show Next hop type: VnetLocal for intra-VNet traffic.
  7. Try again with a destination outside the VNet (e.g., 8.8.8.8) — should show

Internet (traffic exits the VNet).

Useful for validating custom route tables (UDRs) and confirming expected

routing behavior.

Part 6 – Packet capture

⚠️

warning

Packet capture can capture sensitive data (passwords, API keys, etc.) in plaintext. Only capture traffic you intend to analyze, use filters to reduce data, and handle .pcap files securely.

  1. Network Watcher > Packet capture (under Network diagnostic tools) >

+ Add.

  1. Create packet capture:

- Name: capture01

- VM: vm-source

- Network interface: (auto-selected)

- Capture settings:

- Time limit (seconds): 60

- Maximum file size: (default 100 MB)

- Filters (optional): leave empty for now

- Storage account: select or Create new (stores the .pcap file)

- Create — begins capturing.

  1. After ~1 minute (or manually Stop), go to Packet captures > select

capture01 > Download the .pcap file to analyze with Wireshark.

Part 7 – NSG flow logs & Traffic Analytics (concepts)

  1. Network Watcher > NSG flow logs (under Logs) > + Add.
  2. Configure (requires an NSG from a prior lab, e.g., Lab 13):

- Select NSG: choose an NSG

- Target storage account: select or create

- Retention (days): 30

- Traffic Analytics: Enabled (optional, requires a Log Analytics workspace)

  1. Save.

Once enabled:

storage account blob).

minutes and provides visualizations: top talkers, blocked flows, geographic

distribution, etc.

Part 8 – Topology

  1. Network Watcher > Topology (under Monitoring).
  2. Resource group: select rg-az104-lab19 — visualizes VNets, subnets,

NICs, NSGs, and their relationships in a topology diagram.

Validation

Cleanup

  1. Network Watcher > Packet captures > select capture01 > Delete.
  2. Resource groups > select rg-az104-lab19 > Delete resource group.

NetworkWatcherRG is a special auto-created resource group — don't delete it;

it's shared across your subscription's networking diagnostics.

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