How to set up a debian server for network distribution?

Question

Debian

Hello. I got a server with 3 ethernet ports. I have 2 providers at home. Please tell me how to set up the server in order to achieve the following goal:
The Internet from 1 provider enters the server, on a 100 megabit link. IP is static there, it is enough to specify ip, the gateway and the Internet works.
The Internet from 2 providers enters the server, on the second 100 megabit link. The Internet is distributed there by DHCP, but to get access outside the local area, you need to raise an L2TP connection.
From the server, through the third gigabit link, the Internet goes out, directly to the router, from where there will already be wi-fi and not only the Internet will diverge. I want to get an increase in Internet speed, and be able to force traffic to a certain resource through a certain provider.
In principle, I can install another OS instead of debian, but I have been working with debian for a long time, though at the very minimum level, and after setting up the network I want to raise a web server there on nginx.
Thank you.

Answer 1

if it’s simpler then habrahabr.ru/post/160047
also read habrahabr.ru/post/108690 and habrahabr.ru/post/117620