Two subnet, two default gateway

RouterOS General
1

I have to manage two different lan subnet with the same routerboard device, each one with its default gateway (0.0.0.0 route)
i.e. :
eth1 192.168.1.1 (default gateway for this lan) 0.0.0.0/0.0.0.0 routed to 10.0.0.254 attached to eth2 (10.0.0.1)
eth3 192.168.2.1 (default gateway for this lan) 0.0.0.0/0.0.0.0 routed to 20.0.0.254 attached to eth4 (20.0.0.1)

How can I accomplish this at the same time ??

Thank you.

2

Any suggestion ?

It makes me think question is too much simple one can imagine I can sove it myself…(perhaps you’re ok.. :confused: )

When I add a new route , I can set a dst address and a gateway , but no a source address or network,

It would be easy if one can set

source a.a.a.a/24 dst 0.0.0.0/0 gateway a.a.a.z
source b.b.b.b/24 dst 0.0.0.0/0 gateway b.b.b.z

but it seems not possible in route configuration, should I work around routing mark instead ??

Thank you

3

With default config, eth3,4,5 are slave ports to eth2.

Using Winbox, go to Interfaces > Interface and edit eth2,3,4 and 5. In the “Master Port” dropdown, set it to None.

Go to IP > Addresses, remove default entries.

  • Add entry, IP 192.168.1.1, interface Eth1
  • Add entry, IP 10.0.0.1, interface Eth2
  • Add entry, IP 192.168.2.1, interface Eth3
  • Add entry, IP 20.0.0.1, interface Eth4

To make Lan #1 go out Wan #1, and Lan #2 go out Wan #2, you have to mark packets coming in on eth1 and eth3

Go to IP > Firewall, Mangle

  • Add entry, Chain=prerouting, in-interface: eth1, action: mark routing, New Routing Mark: LAN1
  • Add entry, Chain=prerouting, in-interface: eth3, action: mark routing, New Routing Mark: LAN2

Packets leaving a gateway must be masqueraded (so the outbound packets take on the wan interface’s IP).

Go to IP > Firewall, NAT

  • Remove default masquerade rule
  • Add entry, chain: srcnat, Out-Interface: Eth2, Action: Masquerade
  • Add entry, chain: srcnat, Out-Interface: Eth4, Action: Masquerade

Because you use static IPs for your WANs, you need to manually create the routes
Go to IP > Routes

  • Add Entry, Dst. Address: 0.0.0.0/0, Gateway: 10.0.0.254, Routing Mark: LAN1
  • Add Entry, Dst. Address: 0.0.0.0/0, Gateway: 20.0.0.254, Routing Mark: LAN2

I believe that’s it.

4

I was been away for a time.

Van , let me thank you now… :smiley:

Very helpful