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Firewalls and VPNs lab 10 of 16

BGP over redundant tunnels with DPD and BFD

A branch router has one tunnel to a FortiGate and one to a vSRX at head office. Run eBGP over both, prefer the FortiGate in both directions so traffic stays symmetric through one stateful firewall, add BFD and dead peer detection, then break the path to the FortiGate and watch traffic fail over within seconds.

Run this lab

It needs Lite: its 5 nodes are set to 6 vCPU and 7,680 MB in total. That fits the free demo too.

In your workspace: Shared, then Firewalls and VPNs multi-vendor guided labs, then 10 - BGP over redundant tunnels with DPD and BFD

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Level
Advanced
Time
About 110 minutes
Nodes need
6 vCPU, 7,680 MB
Smallest plan
Lite

The scenario

Marden Logistics' branch (BR) has two tunnels to head office, already up: Tunnel1 to the FortiGate (the primary firewall) and Tunnel2 to the vSRX (the backup). Static routes would leave the branch blind when a path fails, so the network team wants BGP over both tunnels, a clear primary, and failover in seconds rather than minutes. Behind both firewalls, CORE (AS 65000) already runs BGP to each of them and advertises the server LAN, 10.0.100.0/24.

DeviceASTunnel addressPeers with
BR65020Tunnel1 169.254.10.1/30, Tunnel2 169.254.10.5/30HQ-FGT 169.254.10.2, HQ-SRX 169.254.10.6
HQ-FGT65010to-BR 169.254.10.2BR 169.254.10.1, CORE 10.0.0.1
HQ-SRX65011st0.0 169.254.10.6/30BR 169.254.10.5, CORE 10.0.0.1
CORE65000(HQ LAN 10.0.0.1/24)10.0.0.2 and 10.0.0.3, already configured
RequirementValue
Branch prefix10.20.0.0/24 (BR Loopback0), advertised to both
Primary pathThrough HQ-FGT in both directions
BFD300 ms, multiplier 3, on both BGP sessions to BR
DPDEvery 10 s on all three IKE SAs

The FortiGate tunnel uses DES only because of the evaluation licence; in production use AES-256-GCM with DH 19, 20 or 21.

What you’ll practise

  • Run eBGP over IPsec tunnels between IOS, FortiGate and Junos
  • Steer both directions with local preference and AS-path prepending, and explain why symmetry matters to stateful firewalls
  • Add BFD to the BGP sessions and DPD to the IKE SAs, and compare what each detects
  • Simulate an ISP fault and measure the failover
  • Verify with show ip bgp, show bfd neighbors, get router info bgp summary and show bgp summary

The tasks

  1. Check the tunnels
  2. eBGP over both tunnels
  3. One primary, both ways
  4. BFD and DPD
  5. Fail over

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 BGP over redundant tunnels with DPD and BFD5 nodes and 1 network, 6 links. Every link is listed as text below the diagram.ISPBRHQ-FGTHQ-SRXCOREHQ-LANGi0/0port2ge-0/0/1Gi0/0port1Gi0/1ge-0/0/0Gi0/2Gi0/0
5 nodes and 1 network, with the interface names each link uses. On a narrow screen, scroll the diagram sideways.
Every link, as text
  • ISP Gi0/0 to HQ-FGT port1
  • ISP Gi0/1 to HQ-SRX ge-0/0/0
  • ISP Gi0/2 to BR Gi0/0
  • HQ-FGT port2 to HQ-LAN (network)
  • HQ-SRX ge-0/0/1 to HQ-LAN (network)
  • CORE Gi0/0 to HQ-LAN (network)
Nodes in BGP over redundant tunnels with DPD and BFD, with the image each runs and the vCPU and RAM it’s set to
NodeDeviceImage in Add NodeSet to
ISPCisco IOSvvios-adventerprisek9-m.spa.159-3.m91 vCPU, 512 MB
BRCisco IOSvvios-adventerprisek9-m.spa.159-3.m91 vCPU, 512 MB
HQ-FGTFortinet FortiGatefortinet-FGT-v7.0.17.M-build06821 vCPU, 2,048 MB
HQ-SRXJuniper vSRX NextGen templatevsrxng-23.4R2-S3.92 vCPU, 4,096 MB
CORECisco IOSvvios-adventerprisek9-m.spa.159-3.m91 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 Firewalls and VPNs multi-vendor guided labs.

  3. Open 10 - BGP over redundant tunnels with DPD and BFD 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 Check Point, Cisco, CompTIA, Fortinet, Juniper Networks, MikroTik, Netgate and Palo Alto Networks. The lab follows exam topics and isn’t vendor training material; vendor names identify the exams and the images in the workspace.