Greetings!
I just wanted to ask if the scenario from the picture is possible and what should be done to make it happen.
I want the USER 1 to get its internet from ISP1 and the USER2 to get its connection from the ISP2.
I hope somebody can enlighten a novice like me. Thanks! 
Could you be more specific about your design choices? For starters I am wondering why you use 2 routers, which would then lead to a third router leading towards a switch leading towards the clients.
To me it seems you make things more complicated than it needs to be. You could configure both ISPs on the central RouterBoard (Router3) easily, eliminating at least two routers from you configuration. Or if you wish to use those two separate routers for each ISPs, why not remove router 3 from you configuration?
As for your question about routing to the designated ISPs, I think you should use Mangle-rules (IP > Mangle) to route towards the correct ISP. Since you use two seperate subnet, use something like this:
/ip firewall mangle
add action=mark-routing chain=prerouting new-routing-mark=isp1 passthrough=yes src-address=192.168.1.0/24
add action=mark-routing chain=prerouting new-routing-mark=isp2 passthrough=yes src-address=172.168.0.0/16
You can now use the routing mark you set to specify a new route forwarding it towards the correct ISP.
On a side note, your design contains a HUGE mistake, your 172.168.0.0/16 is not allowed based on the RFC1918, https://en.wikipedia.org/wiki/Private_network. And I suspect you’d want to use that network as a private network. But correct me if I am wrong.
Thanks for giving me idea and yeah, thanks also for pointing out my mistakes.
So here s another scenario.
User 1 should get their net connection to ISP1 and so isp2:
(user 1) 192.168.1.0/24 ------> ISP1
(user 2) 192.168.2.0/24 -------> ISP2
The two routers (r1 & r2) represents, let’s say two companies. And I want the user1 which is connected to ISP2 to be still communicate with the users from ISP1.
I know it seems complicated but can it be done? I’m not well-versed to networking. I’m a novice so I’m not sure if what I’m talking about even makes sense. But i need this to make it happen.
Thank you so much
Hi,
Depending on your exact needs I think it can be done.
So, assuming from your description we have two separate locations; location A with the 192.168.1.0/24 network and location B with both a 192.168.2.0/24 network and a 192.168.3.0/24.
In order for the user1 in location B, which has an IP-address from the 192.168.3.0/24 network to be able to communicate with devices and users on location A you’ll need to establish a VPN-tunnel, for example an IPSec tunnel, or if both locations use a MikroTik router, consider using a EOIP-tunnel, which is a proprietary protocol of MikroTik. Then you’ll need to use the mangle rules to forward the matching traffic trough the VPN-tunnel so it will get routed towards Location A.
If all users from Location B are allowed to connect towards Location A, life is a bit simpeler, just establish the VPN-tunnel between the two sites and make a route from Router 2 towards Router 1 and backwards.
Where you from, you might be better of with a MikroTik consultant helping you with your configuration if you’ve got the budget to spare.
Thanks sir!
I’ll keep that in mind