So I should use the DNS Servers (18.104.22.168, 22.214.171.124, and 126.96.36.199) of my ISP as monitor IPs? If I do this I can get rid of the static routes I made since pfsense automatically creates static routes when you use them as monitor IPs, correct?
Those should be fine. The static routes aren't necessary when the DNS servers and monitor IPs are the same.
When one link fails, the Status -> Load Balancer screen correctly shows that that link is "OFFLINE", no problem with that.
I also have DNS Forwarding enabled, do you think I should disable this? I think the load balancer pools don't have any problems, really. I think the DNS is what's causing the prob, I don't know.
Using the DNS forwarder is fine. See what the problem is, is it DNS not functioning?
Alright. But if I use different monitor IPs other than the DNS servers, I should do static routes? Also, these modems are all from the same ISP, so they are in one network and they all have access to the SAME three IP addresses, so I think even though I use different monitor IPs, I don't need to do static routes, right?
How will I know if DNS is not functioning? Is there a test that I should perform?
What does "Warning" mean in the Status -> Load Balancer screen?
For example, I make the DNS servers as monitor IPs, pfsense will automatically create static routes right? So say modem2 and modem3 are down, effectively pfsense can just use the first DNS server which is 188.8.131.52 right? Since it won't get responses from the other two because they have static routes to WAN2 and WAN3, correct? Won't that post a problem when modem2 and modem3 are down and at the same time DNS server1 is also down?
Also, in the Diagnostic -> Routes page, usually if I use the DNS servers as monitor IPs the static routes are defined there (184.108.40.206 to default gateway, 220.127.116.11 to 192.168.2.1, and 18.104.22.168 to 192.168.3.1), but sometimes the 22.214.171.124 to 192.168.2.1 static route just disappears, why is that? I have to reapply the load balancing rules for that to take effect again. Why is that happening?