topic Re: ISP Link Redundancy - Load Sharing / Gateway keeps traffic in a single ISP in Firewall and Security Management

ISP Link Redundancy - Load Sharing / Gateway keeps traffic in a single ISP

KrivU — Fri, 26 Sep 2025 21:04:11 GMT

Hi,

I have a cluster configuration, on this, we recently changed the configuration for the ISP Link Redundancy from Primary/BackUp to Load Sharing, the SMS and Gateways are on 81.10 take 99. with two gateways, one called Primary and the other is the BackUp, the ISP Link Redundacy handles three diferent ISP's.

When the traffic is going through the BackUp the ISP Link Redundacy in Load Sharing, works perfectly, we did some fw monitors and the traffic balance between the three ISP's, but if the traffic goes through the Primary-GW sends all the traffic to only one of the three ISP, We tried to run an fw isp_link {name of the ISP} down, and ran a fw monitor, and keeps sending the traffic from the same ISP,

Has anyone else got experience a similiar behavior?

Re: ISP Link Redundancy - Load Sharing / Gateway keeps traffic in a single ISP

the_rock — Sat, 27 Sep 2025 00:09:01 GMT

Can you check the routes on both firewalls to make sure its correct?

Andy

Re: ISP Link Redundancy - Load Sharing / Gateway keeps traffic in a single ISP

KrivU — Sat, 27 Sep 2025 01:21:28 GMT

Thanks for the reply,

Yes, I checked, and the default routes are the same, are pointing to the main ISP, what other items shall I look over?

Re: ISP Link Redundancy - Load Sharing / Gateway keeps traffic in a single ISP

the_rock — Sat, 27 Sep 2025 01:26:29 GMT

Maybe run ip r g 8.8.8.8 from expert mode to confirm its right output.

Andy

Re: ISP Link Redundancy - Load Sharing / Gateway keeps traffic in a single ISP

Chris_Atkinson — Sun, 28 Sep 2025 15:20:39 GMT

Does the issue persists across reboots of that member?

Re: ISP Link Redundancy - Load Sharing / Gateway keeps traffic in a single ISP

the_rock — Sun, 28 Sep 2025 16:06:20 GMT

Excellent point Chris.

Re: ISP Link Redundancy - Load Sharing / Gateway keeps traffic in a single ISP

KrivU — Mon, 29 Sep 2025 14:54:52 GMT

Hi the_rock,

Yes I tried on both of the members of the cluster, when I failover the traffic to the BackUp, and I did the fw monitor, I can see the traffic swiching between ISPs interfaces, but when I failover back the traffic to the primary, in that cluster member the traffic just stays on one of the 3 ISPs

Re: ISP Link Redundancy - Load Sharing / Gateway keeps traffic in a single ISP

KrivU — Mon, 29 Sep 2025 14:56:15 GMT

Hi Chris, thanks for the reply,

I havent tried a reboot, we the TAC we tried a CPSTOP, CPSTART, but nothing changed, I'm going to schedule a reboot, to see the behavior,

Re: ISP Link Redundancy - Load Sharing / Gateway keeps traffic in a single ISP

the_rock — Mon, 29 Sep 2025 15:49:16 GMT

Did TAC give you any other suggestions?

Andy

Re: ISP Link Redundancy - Load Sharing / Gateway keeps traffic in a single ISP

KrivU — Mon, 29 Sep 2025 16:19:24 GMT

No, the case still open, and they are testing in lab environment that's the last update

Re: ISP Link Redundancy - Load Sharing / Gateway keeps traffic in a single ISP

the_rock — Mon, 29 Sep 2025 16:36:50 GMT

Please keep us posted.

Regards,

Andy

Re: ISP Link Redundancy - Load Sharing / Gateway keeps traffic in a single ISP

the_rock — Sun, 05 Oct 2025 22:46:36 GMT

Hey @KrivU

Were you able to figure this out?

Best,

Andy

Re: ISP Link Redundancy - Load Sharing / Gateway keeps traffic in a single ISP

KrivU — Wed, 15 Oct 2025 20:28:44 GMT

Hi @the_rock

We proceed with a reboot of the members of the cluster, and everything is working fine, I've been monitoring the behavior and its working as it suppose to, thanks for the follow up, the TAC told me that could be a configuration on the ISP stickiness on the firewall, but after reboot it wasn't necessary to change anything.

Re: ISP Link Redundancy - Load Sharing / Gateway keeps traffic in a single ISP

the_rock — Wed, 15 Oct 2025 20:38:17 GMT

Awesome job!