System Domain Name – Slow DSL ATT with block of static IP addresses, you want to balance the load with the new Cox fast cable modem

Over the past decade, I have operated multiple mail servers on the only available Internet access provider, ATT. The modem does not get very good signal levels, does not allow an acceptable SNR, and so on. He is stable, but slow. 18down1up

Recently, we managed to wirelessly connect a Cox connection to our site with a much faster speed and much less latency. We use Ubiquiti operator class equipment, massive Yagis ubiquiti coupled with their M900 rockets. Half a mile away. The speed of satellite transmission exceeds the capacity of our equipment and we are going as fast as the antennas can provide it. 50-100 down, 30up

We want to keep the att connection as a backup, in case Cox breaks down. Most importantly, we would like to continue using their static IP addresses. In other words, we want to use the speeds available through Cox, including download capacity, while continuing to use our existing static IP addresses provided by att.

I've set up several ubiquiti mail servers and I can understand all the suggestions. I am however not an expert and I learn mainly through experience. Still a computer student, I just moved to Java.

I am interested in all ideas.

Ideas up to now (have not tried any, not sure if possible):

-Maybe I can just connect a switch to cox wan and the servers will connect to att via cox?
-How to transfer traffic to Cox IP
-VPN to access the network faster and configure the vpn device to use a static IP address. Have dual wans first connected to our on – site modem, and then as vpn via cox to device. Use wan first only when second is not available.
Router loading?
-IPTables / Nat?
-domains dns?

Please excuse what should look like me as a newb. I myself thought that the majority of what I did thought I did not need school, so I decided a few years ago that this school was necessary and that I could not learn everything on the fly. Slowly filling gaps. Please, do not hit me verbally too lol. I have the gift of learning and understanding things very quickly, but I am not yet an expert.

Thank you!!!