Without any deeper knowledge of OpenWRT I try to create three separate VLANs on the MR18. But I fail misserably. Mostly because I cut myself from the management connection
I believe the MR18 doesn't have an internal switch, please correct me if I am wrong.
Then you need to create the 3 interfaces and for ifname use subinterface, e.g eth0.101 for Management
Then create the wireless SSIDs and assign each one of them to the appropriate interface.
Finally configure the firewall accordingly.
I suggest you assign an IP/Mask/GW/DNS only on the Management interface, and leave the other two with unmanaged protocol.
No one said that support for something would be lost...What are you even referring to?
OpenWrt supports VLANs if that's what you mean; but @trendy noted that the MR18 doesn't have a switch, it has a single Ethernet port. It may help to note that VLAN tags don't require a switch, maybe this is different from your understanding of Meraki documentation. You will have to properly setup your interfaces for VLANs.
All three what would get DHCP from the router?
Did you setup the networks yet?
If you're asking if you can use the OpenWrt for DHCP on all your VLANs, that answer is yes
This is a quite simple config to create new networks...the VLAN tagging on the Ethernet port will be the challenge not to lock yourself out; but you seem to be familiar with using a managed switch.
@trendy, @eduperez, @mk24, could you point @Deezer to some threads/documentation on how to setup VLAN tagging on an Ethernet interface?
Yes, sure. There is documentation about guest network, which can be expanded for the internal. Just remember to bridge the wireless interface with the vlan subinterface.
Use subinterface ethX.101 as the physical interface.
Add a new interface in Network/Interfaces and give a name of your liking. For Interface click on the drop down list, enter eth0.101 or eth1.101, that depends on the name that ethernet interface has. For protocol choose static or dhcp client. For firewall settings you may want to add it in a new or existing zone, it's up to you. DHCP settings you will leave then as ignored.
Then create a new Wireless SSID and assign it to the interface you just created.
How can I make LuCI web interface not accessible on the newly created SSID?
Firewall zones. What difference does it make? I managed to put SSID1 on 192.168.1.1/24 (untagged) and SSID2 on 192.168.2.1/24 (tagged 101). Upstream firewall deny traffic between interfaces, so I can't see Firewall zones making a difference...
Either block it on firewall or from the luci config.
That one can bypass the upstream firewall since you have IPs on all interfaces. If you don't want to have the firewall enabled, leave only one management interface with IP and for the rest assign protocol "none".