Replace ISP WAN connection with other router

RouterOS Beginner Basics
1

Hi,

A storm took out my WAN connection (cable physically broke down outside my home). I bought a small travel router with a USB port and my phone is tethered to it and if I connect wirelessly to I can surf the internet (like now).

Now I want this router to drop in replace my WAN connection (temporarily until my ISP is back) but I have no clue how to do this. My WAN cable was connected to ether1 interface and it was configured with PPPOE

The new travel router issues IPs in the 192.168.8 range, my mikrotik RouterOS 6 issues in 192.168.0 range.

I connected a cable between LAN travel router and ether1 Mikrotik. The Mikrotik has wireless and wired connections I want to keep exactly the same.
I have no idea what to configure, attached screenshot with how I have it connected now.

Presumably I have to disable the VLAN and PPPOE entries in the interface list but not sure what to replace it with.
The travel router does hand out 192.168.8.120 and I see something in Routes but no idea what to do.

Any help greatly appreciated!
Screenshot_2025-02-05_19-21-57.png
Screenshot_2025-02-05_18-47-39.png

2

I would keep ether1 setup as is and use a different port as WAN2 to the router, do you have a spare port?

3

I do, so do I create a new WAN2 interface in Interfaces? I will give it a try.

4

I have no idea what I am doing, I created a new WAN2 in Interface Lists
ether3 is connected to the LAN port of the travel router which has 8.120 as IP address.

But how do I assign ether3 to WAN2 and route all nonlocal traffic to it?
Screenshot_2025-02-05_20-38-05.png
Screenshot_2025-02-05_20-37-09.png

5

You made a new interface list, called it WAN2 and added to it ether3.

This only adds an entry to a new list (that you don’t want and don’t need). You only want the (default) LAN and WAN lists as they are referenced to in other parts of the configuration (firewall) and without changes this may prevent connection through any interface that Is not in those two default lists.

You need to:

  1. remove ether3 from bridge
  2. add to ether3 a DHCP client (I am assuming that your travel router has a DHCP server running)
  3. add ether3 to existing interface list WAN
  4. delete the WAN2 interface list

Now check your ip addresses and ip routes.
Ether3 should have a Dynamic address in the subnet of the travel router and there should be a Dynamic route with 0.0.0.0 with gateway 192.168.8.120 besides the “old” route with the ether1 or pppoe interface or address as gateway.
Very likely this route is already not Active whilst the new one going to the travel router Is Active.
Otherwise disable (temporarily) ether1.
Check that in ip firewall nat you have a srcnat action=masquerade rule with out-interface-list=WAN (this is the default configuration).
If you have instead one with out-interface=ether1, make a new identical one with out-interface=ether3.

6

Thanks a lot! I think I understand what you say, I will try it.

I see one downside for me here: I have some static ip and other stuff setup on 192.168.0 subnet. If I make the travel router the DHCP server it will be 192.168.8
I guess I can change the subnet to 192.168.0 to avoid major changes

Thanks again, I will try

EDIT on re-reading, maybe it’s not necessary as the assigning will stop at ether3?

7

Success! Thank you very much!

8

Yep, once It Is taken out of the bridge, what happens in ether3 stays in ether3 :wink: .