In Meraki MX HA architecture, will the spare MX (LAN Ports) still be functioning as a L2 switch

[Oucean]

Hello Everyone

Our customer has a Meraki network that only contains MX Security Appliance. Since the customer wants to avoid one more failure point and also to save cost, they didn't purchase MS Switch for this network. Now the customer wants to enable HA architecture for this MX only network. So I'm thinking if two MX appliances (of course the same model) can enable HA without an MS switch and hosts under two MX appliances can all work fine?

For example, like below topology. VLAN 101 was created on both MX appliance with private IP address 10.1.1.1/24. This VLAN is used to connect with each other and to the hosts under them. So when the Secondary MX works in Spare mode, will its LAN part still be functioning as a L2 switch and make the Server 2 be able to access Internet via Primary MX?

I know the best way to confirm this is just to do a test, but I'm sorry currently I don't have the environment to do the test. Only if it can work, the customer will purchase the secondary MX appliance. So I raised this post to request everyone's help. May I know if any one tried this way and is it working fine? Thanks very much in advance.

[Ryan_Miles · Accepted solution]

Yes it would work. But as shown if your primary MX fails your Server 1 becomes unreachable.

[Oucean]

Hello Ruan

Thanks a lot for your reply~

And yes, if primary MX is down Server 1 will be unreachable. Actually that's an expected situation. If we use two switches, and if one switch is down, the server under that switch will also become unreachable. So in fact, both servers are also HA build for one service.

Now I got what should I do. Many thanks again for your kindly help.