Hmm.. on Zentyal GUI, I followed the instructions in the documentation on adding gateways with corresponding weights. This is what I meant, base on Zentyal GUI, everything is perfect, because you can see the gateways you added in the list, you can ping the gateways in the diagnostics tools, and confident that the gateways are working by using zentyal's firefox, then checking the public ip one by one (three public IP's). But what I see in the GUI is different from the CLI, no default gateways on the CLI list. Is this normal?
Back to Zentyal GUI, I also enabled traffic balance and wan failover on my three WAN's.
Thanks!