comments:
u/inaneshane described my setup below. I have a UniFi Cloud Gateway Fiber with an SFP+ module using the 8311 firmware. I used passthrough for some time as well. Once I discovered that the fill bypass was relatively easy to do and well-supported ( the PON dot Wiki site is the best information source ), I jumped in. Even buying the SFP+ stick was easy - I actually found mine on Amazon, of all places.
This is the one I picked up, Several folks on the YouTube video I had watched commented that it worked with ubiquiti as did some of the amazon reviews, so I assumed that it would work with the UDM https://www.amazon.com/dp/B0FT74L89Y?ref=ppx_yo2ov_dt_b_fed_asin_title
Here's what I used: UniFi Cloud Gateway Fiber This SFP+ module. I was shocked to find these on Amazon, but it already has the required 8311 firmware installed. Works perfectly. UniFi U6 WiFi APs (2) in a mesh. The Cloud Gateway has no wireless, so this is a necessity. The methodology for doing this can be found at this website. Read the page explaining why folks do this, gives a lot of detail. There's also an 8311 Discord server where a lot of people hang out with useful information. The benefit is that by eliminating the AT&T gateway and bringing your fiber line directly into your equipment, you have full control of your network. In passthrough mode, you still have issues with double NATting and other things. The UniFi gateway has a web-enabled network operating system that allows you full control of all network settings. This gateway has a solid firewall and IDS/IPS and an endless number of configuration options. I chose to use UniFi in this way because all their device are integrated and completely manageable from the web console. (I also have two UniFi 1 gigabit switches on this network). Hope this is helpful.