Trying to config same subnet on two physical ports per firewall in HA

SipriusPT

Hello everyone,

I am trying to config a subnet to use two interfaces in on firewall, in this case there is a switch integrated, in order if one fails, the other maintain the network.

This is the network layout that I am trying to achieve:

LAN_interface_HA.drawio (2).png

The problem is that I have two firewalls sync, and if I config a second port to use the same subnet, in both, when connect it to LAN SWITCH B, that would freak out both firewalls, having loss of connections with WAN, and in both log consoles, I see lots of blocks for that, even when disconnecting the second port in each firewall. Its like there is a loop in those interfaces.

So my question is, to achieve this, I am obligated to use a different subnet to be used in LAN SWITCH B, without any firewall restriction between both subnets? or I can use the same subnet? if yes how can I achieve this?

If you need more info just let me know.

Thanks in advance!