VLANs help, sanity check for my first implementation

RouterOS General
1

I have a Router (chateau) which is connected to a CSS326 providing internet over 5g.Only 1 cable is available from Chateau to CSSswitch. Mikrotik eth2 connects to CSS326 eth1 . Currently the chateau has a common router setup, where eth2-5 are in a LAN bridge, and eth1 is not connected anywhere. Chateau provides addresses through DHCP Server on my LAN , in the range of 192.168.2.0/24.

I wanna connect another ISP router to eth10 of switch so that the chateau has a fallback connection for when the 5g is not available. The ISP provides DHCP (which i cannot disable) in the range of 192.168.1.0/24.

Since both routers provide different DHCP servers ( and i want only my Chateau to provide the DHCP for my LAN) My thought is that i should MARK the VLAN (EG 100) on eth10 of the switch, so that the ISPs DHCP doesn’t show up on my LAN. then make port2 of Chateau a trunk port, that will be part of both the Vlan 100 and the LAN bridge. this way, i will be able to setup a DHCP Client on the VLAN100 interface, and give addresses through the Lan Bridge to my other 23 ports of the switch.

Am i thinking something wrong with this setup?

2

The second ISP is connected at the CSS?
Than you’re on the right track, add a VLAN of your choice on both devices (see documentation for CSS), for the Chareau I recommend to use a simple vlan Interface as a sub for eth2.
Next step is to add a DHCP client to that vlan interface (without default route), and then manually add a second default route facing that Interfaces gateway with a higher distance, let’s say 5. Add masquerading and firewall to your desire, done.

3

My bad, forgot that you can change the default route distance in the dhcp client, go for that instead.

4

yes the second ISP is connected to the CSS .

i will add the vlan there, but on chateau , should i add the vlan on the eth2 , or on the LAN bridge that eth2 belongs to?