Same IP on different Ether interfaces

RouterOS Beginner Basics
1

Hi there

I have been trying to configure my mikrotk RB4011 to be able to have a device with the same IP address on each interface of the router. I have seen on other forum posts that this seems to be doable but I cannot seem to get it to work.

http://forum.mikrotik.com/t/connecting-to-multiple-devices-with-same-ip-address/159052/1

I have put my setup below hopefully I’m doing something stupid.

/ip address
add address=192.168.1.12/24 interface=ether1 network=192.168.1.0
add address=192.168.1.13/24 interface=ether1 network=192.168.1.0
add address=192.168.1.14/24 interface=ether1 network=192.168.1.0
add address=10.0.0.1 interface=ether2 network=10.0.0.1
add address=10.0.0.1 interface=ether3 network=10.0.0.1
add address=10.0.0.1 interface=ether4 network=10.0.0.1

/routing/table
add name=port2 fib
add name=port3 fib
add name=port4 fib

/ip firewall mangle
add action=mark-connection chain=prerouting dst-address=192.168.1.12 new-connection-mark=port2
add action=mark-connection chain=prerouting dst-address=192.168.1.13 new-connection-mark=port3
add action=mark-connection chain=prerouting dst-address=192.168.1.14 new-connection-mark=port4
add action=mark-routing chain=prerouting connection-mark=port2 new-routing-mark=port2 passthrough=no
add action=mark-routing chain=prerouting connection-mark=port3 new-routing-mark=port3 passthrough=no
add action=mark-routing chain=prerouting connection-mark=port4 new-routing-mark=port4 passthrough=no

/ip firewall nat
add action=dst-nat chain=dstnat dst-address=192.168.1.12 dst-port=443 protocol=tcp to-addresses=10.0.0.120
add action=dst-nat chain=dstnat dst-address=192.168.1.13 dst-port=443 protocol=tcp to-addresses=10.0.0.120
add action=dst-nat chain=dstnat dst-address=192.168.1.14 dst-port=443 protocol=tcp to-addresses=10.0.0.120
add action=masquerade chain=srcnat out-interface=ether2
add action=masquerade chain=srcnat out-interface=ether3
add action=masquerade chain=srcnat out-interface=ether4

/ip route
add distance=1 dst-address=10.0.0.1/24 gateway=ether2 routing-table=port2
add distance=1 dst-address=10.0.0.1/24 gateway=ether3 routing-table=port3
add distance=1 dst-address=10.0.0.1/24 gateway=ether3 routing-table=port4
2

You aren’t using your routing marks in your three static routes at the end. Without them, the rules are redundant, so that only one takes effect.

3

Okay, so that makes sense. Originally I did have route-mark but I get an error when I try and add the route.

 add distance=1 dst-address=10.0.0.1/24 gateway=ether2 routing-mark=port2             
expected end of command (line 1 column 55)

Do you know why I would be getting that error?

4

Hello,

Change this : 10.0.0.1/24 to 10.0.0.1/32

Regards,

5

Do you mean

/ip route
add distance=1 dst-address=10.0.0.1/32 gateway=ether2 routing-mark=port2
6

While subnet is /32 based /ip/address, the issue isn’t the /24. But more likely
routing-mark=port2
vs.
routing-table=port2

That’s why you’re getting a command error. Now is routing “mark” in the firewall, it a “table” routes.

7

Sorry, I don’t know what you mean

8

/ip route
add distance=1 dst-address=10.0.0.1/32 gateway=ether2 routing**-table**=port2

9

You’re referring indirectly to guides from 2016 and 2018, which would be for RouterOS 6. Presuming you’re on 7, this page in the docs is likely to be on-point.

10

VRF, That is what I needed. I then found this video

https://youtu.be/-hdLsXd9OgE?si=Jfu88aqjNCVzDbpL

I am now able to ping 8.8.8.8 but I can’t ping google.com. I believe the domain name isn’t being resolved.

Do i have to forward the DNS? if so how do I do that?

The devices that are connected to the ether port interfaces have the IP addresses setup

IP 10.0.0.120/24
GW 10.0.0.1
DNS 10.0.0.1

11

Yes,

ip dns set allow-remote-requests=yes servers=1.1.1.1 (or whatever dns server you want)
If you do that, make sure your firewall rules are properly configured.