Meraki MX in Single LAN mode

[meraki-user]

Meraki docs say that the MX advertises OSPF routes into the LAN, redistributing routes learned from Auto-VPN... but only in Single LAN mode! So, if the MX is in VLANs mode, how do the other routers in the LAN (for example, MS switches with OSPF enabled) learn those routes?

Also, if the MX is in Single LAN mode, doesn't this disable its routing functionality?

[ww]

In routed mode with vlans, Then you need to use static routes on mx and L3 switch.

In routed mode without vlans you still need static routes on  the mx

[meraki-user]

I know that the MX needs static routes. But with VLANs mode enabled, requiring static routes on the L3 switches (or other neighboring routers) is the part that sounds crazy. Why does turning on VLANs disable the outbound OSPF, forcing the customer to either type static routes on the other devices for all the subnets learned via Auto-VPN, or use the MX as the default gateway for all traffic. 
And the second part of my question is, if the MX is in Single LAN mode, doesn't that disable the routing function? How is that still considered Routed mode, if the MX has only one IP address in one subnet? 

[ww]

Without vlan its still considered routed mode because your mx is still inline and doing the routing from lan to wan/vpn.

I agree meraki ospf has strange limitations. Not learning ospf routes is also one of them.

[meraki-user]

How is the MX able to route between LAN and WAN if it only has one IP address? 

[Brash · Accepted solution]

In single LAN routed mode, you MX has one WAN IP and a single LAN subnet.

The MX will be the gateway for that LAN

subnet. 

LAN IP's are NAT'd out the WAN IP

[meraki-user]

Okay, mystery solved. I see what I was missing. The WAN IP address is not on the "Configure > Addressing & VLANs" page, it's on the "Monitor > Appliance Status" page. In fact, there are a lot of configuration settings that are under Monitor rather than Configure. So, when VLANs mode is not enabled, there must be two internal VLANs not visible to the customer, one for the WAN side and one for the LAN side.