When multiple gateways are used in an ECMP (Equal Cost Multi-Path) configuration, the check-gateway option ensures that RouterOS will actively monitor the health of each gateway using ping (or ARP). If a gateway becomes unreachable, RouterOS temporarily removes it from the active ECMP gateway list.
A.✘Incorrect – Unreachable gateways are excluded from packet forwarding.
B.✔Correct – Only reachable gateways are used in the ECMP round robin logic.
C.✘Incorrect – The entire ECMP route remains active; only the failed gateway is excluded.
Extract from MTCNA Course Material – ECMP Routing:
“With check-gateway enabled, RouterOS will exclude unreachable gateways from ECMP rotation.”
Extract from MikroTik Wiki – Check-Gateway Option:
“When a gateway is unreachable, it is skipped in ECMP logic until it becomes reachable again.”
Extract from René Meneses Study Guide – ECMP and Gateway Monitoring:
“Check-gateway helps prevent blackholing by skipping dead gateways. The route remains active.”
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