Member Avatar for bakra

Hello,

I have this problem, that I can not resolve (I'm too green for in this staff).

so...
I have RouterBoard 750 with RouterOS v3.29 in office.
We have 2 different internet providers ("Online" and "Wanex"), I want to connect both of them in RB 750.
I've pluged Online in first interface and want it to come out in third one, Wanex into second and want it to come out in forth interface.

[img][/img]

I also created 2 gateways ( for Online and for Wanex, both have there own DHCP servers), which are working properly.

[img][/img]

also I've done this and I don't know if this is correct.

[img][/img]

This are routes:

[img][/img]

so, what I want is to seperate 2 ISP in LAN with different gateways (users that are under to use Online and under - Wanex) and same time have 1 network, so that they can share files, if possible.

I will very greatfull if you help me, my job depends on it :(
thanks

P.S.
sorry for my poor english.

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  • Latest Post Latest Post by pmorris1

Dani AI

Generated

Short summary and recommended approach

The cleanest, most reliable design is to let the RB750 be the LAN gateway and DHCP authority, split the LAN into two address pools (or reservation groups) and use policy-based routing so traffic from each pool egresses through its assigned ISP. That follows the intent in 's suggestion (mark traffic by source network) but fills in a few practical items missing from the thread.

Key implementation notes

  • Make the router the authoritative DHCP server and assign clients into two pools (or static leases) so source IP ranges uniquely identify which ISP they should use. This avoids conflicting upstream DHCP servers and ARP confusion.
  • Use policy routing (routing marks based on the source pool) to steer traffic to each ISP.
  • Create NAT (SNAT/masquerade) rules tied to each WAN interface so return packets leave the same ISP they entered on — this prevents asymmetric routing and broken connections.
  • Add route health checks (ping/check-gateway) or route distances so a failed upstream link can be detected and handled cleanly.
  • Ensure firewall forward rules allow established/related traffic between the pools if inter-subnet communication is required.

File-sharing and discovery caveat

Splitting into two IP subnets will still allow normal TCP/UDP file sharing (routing through the RB), but broadcast-based discovery (NetBIOS/LLMNR/mDNS) will not cross subnets by default. Options are: keep a single L2 domain and assign per-host routing (more brittle), run a central name/WINS server, or allow specific ports/proxies so services remain discoverable.

Troubleshooting checklist

Verify mangle/routing-mark counters, NAT hit counters, and run traceroutes from representative clients to confirm egress. Test failover by simulating a WAN failure. Also confirm no upstream DHCP servers are conflicting; if they are currently active, put them in bridge mode or disable their DHCP.

This approach gives predictable routing, avoids double-DHCP/NAT problems, and keeps local traffic routable while steering Internet traffic per group.

Member Avatar for pmorris1

what you seem to be looking to do is, based on which network they come from, send traffic out a particular gateway.

use gateway Online
use gateway Wanex

I typically use the CLI with mikrotik so that is the way I will provide this.

First, you want to setup some marking for packets sourced from the two different LAN networks:

ip firewall mangle> add src-address= action=mark-routing new-routing-mark=Online-WAN chain=prerouting

ip firewall mangle> add src-address= action=mark-routing new-routing-mark=Wanex-WAN chain=prerouting


Second, you need to setup the routing to use these markings for each gateway:

ip route> add gateway=<public IP GW for Online ISP> routing-mark=Online-WAN check-gateway=ping

ip route> add gateway=<public IP GW for Wanex ISP> routing-mark=Wanex-WAN check-gateway=ping

ip route> add gateway=<public IP of any ISP>


You will be able to re-name the route-mark to whatever you like. Also make sure you fill in the correct IP of each gateway in the last set of config commands. The third gateway added is kind of like a default gateway for the default gateway, as it is setup to check to make sure the first two are working.

This should fix your issue, or at the very least, a good start.

cheers
phillipq

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