Using the files from https://github.com/jaysoffian/eap_proxy these are the instructions to get a fully functional bypass using a EdgeRouter Lite and AT&T router.
Searching multiple places I could only find snippets and partial code. After piecing these together I got a working config.
Kudos to https://www.reddit.com/user/SScorpio/ that provided most if not all of the script from https://www.reddit.com/r/uverse/comments/9ii4t5/eli5_how_to_use_eaproxy_and_att_uverse/e9fbtoa?utm_source=share&utm_medium=web2x
I've used this only with a EdgeRouter Lite (ERL), but probably would work with most EdgeOS routers.
This guide configures the ERL ports with the following: