How to set up Mikrotik for 3 providers?

Question

Mikrotik

It’s not very good in micros and networks, please tell me how to do it and is it possible to do it

The office uses 3 Internet channels:

1. Ecotelecom "A" (for servers): the router receives a "gray" ip address from the provider via dhcp, but on the side provider permanent external address. All ports are also forwarded from the external to the "gray" internal.
2. SevenSky "C" (for office computers): the router receives settings from the ISP via pppoe.
3. TRC "B" (for manual) the router receives settings from the provider via dhcp.

The servers in the office have static settings for the main gateway 192.168.1.1 (micro A), so all servers access the Internet through the Ecotelecom channel.

On micrograph B 192.168.1.3, through the marking rules, it is indicated that 1 PC accesses the Internet through the TRK channel, telephone sets through the Ecotelecom channel, and all other PCs in the office through SevenSky.

The difficulty arises in the fact that if all three channels are entered into one router, then it is impossible to register static routes, since Ecotelecom and TPK distribute a different internal ip address each time

Answer 1

https://wiki.mikrotik.com/wiki/Manual:IP/DHCP_Clie...

Answer 2

go to interfaces reassign logical interfaces there to PPPOE or whatever you have to combine into a bridge