MULTI-WAN link showing 'DOWN'

@filippo_carletti I set the multi WAN mode to Active backup, and configured the NIC as follows:

enp3s0

enp3s0 - pci Realtek Semiconductor Co. Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 06)

Link status is up
Speed 100 Mbit/s
Driver r8169
Mac address [redacted]

Role RED

IP: 192.168.1.2
Subnet: 255.255.255.0
Gateway: 192.168.1.1
Name: red40
Weight: 100

enp4s0

enp4s0 - pci Realtek Semiconductor Co. Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 06)

Link status is up
Speed 100 Mbit/s
Driver r8169
Mac address [redacted]

Role RED

IP: 192.168.15.2
Subnet: 255.255.255.0
Gateway: 192.168.15.1
Name: red41
Weight: 100

Next, I checked this:

# shorewall status -i | grep Interface
Interface enp3s0 is Disabled
Interface enp4s0 is Disabled

Thus, ran the command you provided, to get both of them up. So, in the Dashboard section, the Multi WAN section showed both as UP.

However, still unable to get internet access. Tried ping from the server:

# ping google.com
ping: google.com: Name or service not known

Please note that this server has the ASUS H270M Plus motherboard with the problem where, on switching on the server, we need to run the “signal-event interface-update” command to get the network up. Please refer to this post where you and @giacomo have advised us, previously: Networking issues after installing AD

The weird thing is, we have to physically unplug any one of the two NIC and only then does the system work (after running the “signal-event interface-update” command). Simply releasing the role doesn’t work.

Please let me know if there’s any further data I can provide you, to help figure this out.