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FortiGate lab 22 of 25

Diagnostics: sniffer, debug flow and resources

Work two real tickets with FortiGate's own tools: the packet sniffer to see what is on the wire, debug flow to see why the FortiGate dropped or routed a packet, the session table, and the CPU, memory and conserve-mode checks you run when the unit itself is in trouble.

Run this lab

It needs Lite: its 4 nodes are set to 4 vCPU and 5,632 MB in total. That fits the free demo too.

In your workspace: Shared, then FortiGate NSE 4 guided labs, then 22 - Diagnostics - sniffer debug flow and resources

Try it free for 30 minutesRun it on Lite from £3 a day

The free demo needs no card and no email. Every lab plan includes every guided lab.

Level
Intermediate
Time
About 60 minutes
Nodes need
4 vCPU, 5,632 MB
Smallest plan
Lite

The scenario

Two tickets are waiting for you at Harbourside's service desk. Ticket 1: "news.example.net has stopped working, everything else is fine." Ticket 2: "games.example.org (our marketing team's supplier portal, honestly) times out." Nobody remembers changing anything. Work both tickets with FortiGate's diagnostic tools, fix the causes, and then check the health of the firewall itself.

DeviceInterfaceAddressConnects to
FGT1port1 (ISP-A)203.0.113.1/24INET, gateway 203.0.113.254
FGT1port2 (LAN)10.1.10.1/24PC1 10.1.10.10, H1 by DHCP
INET—198.51.100.0/24www .10, news .11, games .12, DNS .53

What you’ll practise

  • Capture traffic with diagnose sniffer packet at the right verbosity
  • Trace a packet's path through FortiOS with debug flow and read the messages
  • Use the session table to see, filter and clear sessions safely
  • Check CPU, memory and conserve mode, and know what conserve mode does
  • Check physical and network-layer health of an interface

The tasks

  1. Start the lab
  2. Reproduce, then sniff
  3. Debug flow for ticket 1
  4. Ticket 2 with both tools
  5. The session table
  6. CPU, memory and conserve mode
  7. Physical and network-layer checks

The Lab Tasks pane has the scenario, these tasks, the checks to run, hints and the full solution.

Topology and devices

The network as it opens in EVE-NG, drawn from the lab’s own canvas, and the image each node runs.

Topology of Diagnostics - sniffer debug flow and resources4 nodes and 1 network, 4 links. Every link is listed as text below the diagram.FGT1INETPC1H1LANport2eth0eth0port1eth0
4 nodes and 1 network, with the interface names each link uses.
Every link, as text
  • FGT1 port1 to INET eth0
  • FGT1 port2 to LAN (network)
  • PC1 eth0 to LAN (network)
  • H1 eth0 to LAN (network)
Nodes in Diagnostics: sniffer, debug flow and resources, with the image each runs and the vCPU and RAM it’s set to
NodeDeviceImage in Add NodeSet to
FGT1Fortinet FortiGatefortinet-FGT-v7.0.17.M-build06821 vCPU, 2,048 MB
INETEVE-NG GUI server (Docker)eve-gui-server:latest1 vCPU, 1,024 MB
PC1EVE-NG GUI server (Docker)eve-gui-server:latest1 vCPU, 2,048 MB
H1Alpine Linuxclbalpinebase-alpine-base-3-20-31 vCPU, 512 MB

How to open this lab

  1. Sign in to your workspace at lab.cloudlabbox.com.

  2. In File Manager, open Shared, then the folder FortiGate NSE 4 guided labs.

  3. Open 22 - Diagnostics - sniffer debug flow and resources and start its nodes, then open Lab Tasks for the scenario and the steps.

The lab is read-only. You can start the nodes and configure the devices, but changes to the topology can’t be saved. To change it, rebuild it in your own folder.

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CloudLabBox is independent of Fortinet. The lab follows exam topics and isn’t vendor training material; vendor names identify the exams and the images in the workspace.