You can use the check_ping probe for that.

As you monitor over the Internet you would need to sourceNAT  the ping_probe traffic for the secondary remote WAN connection checks to another public ip on the Observium side and add a destination route for that sourceNAT’ed ip (host route) on the remote Microtik’s second WAN interface to avoid asymmetric routing.

hth,
Alex

From: observium <observium-bounces@observium.org> On Behalf Of Luis Olavarrieta via observium
Sent: Wednesday, 9 June 2021 14:46
To: observium@observium.org
Cc: Luis Olavarrieta <luis.olavarrieta@wynnmex.com>
Subject: [Observium] monitoring traffic in a redundant internet access

Hey team, question, is there a way to monitor in a mikrotik with two internet access if both are active? The main link will give us remote snmp access to the equipment but we need to know if there is a way we can verify that the 2^nd link that is connected to a DSL modem is up and running.