fortigate ha active-active - lacp connection to single switch or another fortigate

Forum|Forum|8 days ago
July 8, 2026
1 reply
42 views

I’m trying to setup LACP between Fortigate HA Active-Active cluster and another device (switch or another fortigate). On Fortigate HA, only one link to the primary is active and passing traffic.

There is documentation for HA Active-Passive to prevent sending traffic to the slave(“set lacp-ha-secondary enable” ).

Is there any m-lag configuration option on Fortigate HA ?.

Thanks,

FortiGate

funkylicious

SuperUser

maybe this KB will help with an answer

"jack of all trades, master of none"

ebyAuthor

Explorer

Thanks, have already seen this. I’m interested in lacp from single fortigate to fortigate HA(Active-Active). The document says the switch need to support m-lag.

With default LACP setting, only one link is active on Fortigate HA(Active-Active) and that too to the Primary, which defeat the purpose of Active-Active.

LACP status on Single Fortigate to Fortigate HA(Secondary).

link status: up
LACP state: negotiating
LACPDUs RX/TX: 24/34
actor state: ASAODD
actor port number/key/priority: 1 33 255
partner state: ASAIDD
partner port number/key/priority: 1 33 255
aggregator ID: 1
RX state: CURRENT 6
MUX state: WAITING 2

I’m not aware of fortigate supporting anything other than 802.3ad aggregate.

thanks,

funkylicious

SuperUser

based on my understanding of how it works ( HA A/A ) you cannot form a single LACP with 2 distinct FGT to a switch since they are not treated as a single unit, but rather go the classical way of LACP with each FGT it’s own LAG.

the traffic will always reach the PRI and it will distribute the packets accordingly

"jack of all trades, master of none"

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