CloudLabBox
Try the free demo

MikroTik MTCRE lab 2 of 14

Recursive next hops, scope and dual-ISP fail-over

Build dual-ISP fail-over that notices an outage beyond the provider's first router: pin a probe host to each provider, make the default routes recursive through those hosts with scope and target-scope, check them with ping, and stop the probes leaking through the other provider.

Run this lab

It needs Lite: its 5 nodes are set to 5 vCPU and 2,048 MB in total. That fits the free demo too.

In your workspace: Shared, then MikroTik MTCRE RouterOS v7 guided labs, then 02 - Recursive next hops scope and dual-ISP fail-over

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
Advanced
Time
About 60 minutes
Nodes need
5 vCPU, 2,048 MB
Smallest plan
Lite

The scenario

An insurance broker pays for two Internet lines from different providers. Last month ISP1's own upstream failed: ISP1's router kept answering, so the broker's router never switched to ISP2 and the office was offline for three hours. You'll build fail-over that tests the path through each provider to the Internet, not just the provider's first router.

DeviceInterfaceAddress
GWether1 (WAN1) · ether2 (WAN2) · ether3 (LAN)203.0.113.2/30 · 198.51.100.2/30 · 192.168.1.1/24
ISP1ether1 · ether2 (upstream)203.0.113.1/30 · 10.1.0.1/30
ISP2ether1 · ether2 (upstream)198.51.100.1/30 · 10.2.0.1/30
Core (the Internet)internet loopbackweb 192.0.2.10; probe targets 192.0.2.101 and 192.0.2.102
PC1eth0192.168.1.10/24, gateway .1

What you’ll practise

  • Explain scope and target-scope and how RouterOS resolves a gateway
  • Build host routes that pin a monitoring address to one provider
  • Build recursive default routes with target-scope and check-gateway
  • Show why check-gateway on the first hop alone misses upstream failures
  • Prevent probe leaks with blackhole routes, and NAT out of two WANs

The tasks

  1. Understand scope and target-scope
  2. Pin a probe target to each provider
  3. Build recursive default routes
  4. NAT out of both providers
  5. Fail ISP1's upstream
  6. Stop the probes leaking through the other provider

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 Recursive next hops scope and dual-ISP fail-over5 nodes, 5 links. Every link is listed as text below the diagram.ISP1ISP2CoreGWPC1ether3eth0ether1ether1ether2ether1ether2ether1ether2ether2
5 nodes, with the interface names each link uses. On a narrow screen, scroll the diagram sideways.
Every link, as text
  • GW ether1 to ISP1 ether1
  • GW ether2 to ISP2 ether1
  • ISP1 ether2 to Core ether1
  • ISP2 ether2 to Core ether2
  • GW ether3 to PC1 eth0
Nodes in Recursive next hops, scope and dual-ISP fail-over, with the image each runs and the vCPU and RAM it’s set to
NodeDeviceImage in Add NodeSet to
ISP1MikroTik RouterOSmikrotik-7.14.21 vCPU, 256 MB
ISP2MikroTik RouterOSmikrotik-7.14.21 vCPU, 256 MB
CoreMikroTik RouterOSmikrotik-7.14.21 vCPU, 256 MB
GWMikroTik RouterOSmikrotik-7.14.21 vCPU, 256 MB
PC1VPCS hostBuilt in to EVE-NGCounted as 1 vCPU, 1,024 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 MikroTik MTCRE RouterOS v7 guided labs.

  3. Open 02 - Recursive next hops scope and dual-ISP fail-over 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.

More MikroTik MTCRE labs

All MikroTik MTCRE labs

Related labs in other courses

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