Mikrotik - port forwarding through two providers?

Question

Mikrotik

There is a router initially configured according to the manual https://geektimes.com/post/186284/
You need to forward several ports at once to all 3 providers.
Now if you duplicate the rule, it only works on the main provider.
It is necessary that all ports be simultaneously available from 3 providers at once.

Answer 1

It's muddy in your mangle config. For some reason, connection marking goes in the input chain, although it is more correct to do it on prerouting.
I would do this:
/ip firewall mangle
add action=mark-connection chain=prerouting connection-mark=no-mark in-interface=vlan101 new-connection-mark = cm-ISP101 passthrough=yes
***repeat for the other two providers .
This rule will process both connections addressed to the router (input) and everything that is intended to be passed to nat
/ip firewall mangle
add action=mark-routing chain=prerouting connection-mark=cm-ISP101 new-routing-mark=rm101 passthrough= yes
** repeat for the other two providers.
This rule should be located below the previous one. It will put a routing label for the packets on the connections that we labeled cm-ISP101 through cm-ISP103 above. For those
/ip firewall mangle
add action=mark-routing chain=output connection-mark=cm-ISP101 new-routing-mark=rm101 passthrough=yes
** repeat for the other two providers.
This rule repeats the previous one, but applies to those packets that the router generates itself - they do not go through the prerouting chain.
The NAT rules and the routing table seem to be normal for you.