Warm Failover

[Gordon]

We currently have two MX84 firewalls setup with a 1GB connection (I know with the mx84 we only get 500MB but we get a real good price on the 1GB - $0)

We are in the process of adding a backup ISP but it is going to be limited. and we only want it to be used as a last resort.   From reading the order of failover is 

Primary - WAN 1

Primary - WAN 2

Secondary - WAN 1

Secondary - WAN 2

So if we only plug the device in to the Secondary would this achieve what we want or are there any issues to be considered.

[ww]

Yes.

But how many times the secondary mx  wan1 would still  work if the primary  wan1  is down. I guess  only when there is a bad cable.

[PhilipDAth]

That ordering is correct.

[CptnCrnch]

It's explained here (including Cellular backup): 

https://documentation.meraki.com/MX/Deployment_Guides/MX_Warm_Spare_-_High_Availability_Pair#Cellula...

[Gordon]

I have been putting some thought in to this and was wondering if either of these would work.  I only want to use ISP 2 as a last resort since it is a cellular device connected to the WAN port.

I don't have test environment to try this.

Primary WAN 1 - ISP 1

Primary WAN 2 - ISP 1

Secondary WAN 1 - ISP 1

Secondary WAN 2 - ISP 2

or 

Primary WAN 1 - ISP 1

Primary WAN 2 - no used

Secondary WAN 1 - ISP 1

Secondary WAN 2 - ISP 2

[CptnCrnch]

Haven't tested it but from a logical perspective it shoud work. At least if MX1 does'nt have WAN2 to fail over, there's no other chance than to fail over to MX2.

[Nick]

I would go with the secondary setup there

Primary WAN 1 - ISP 1
Primary WAN 2 - no used
Secondary WAN 1 - ISP 1
Secondary WAN 2 - ISP 2

[Gordon]

So I ran a test on the weekend using the following

Primary WAN1 - ISP1

Primary WAN2 - ISP2

Secondary WAN1 - ISP1

Secondary WAN2 - not used.

This did work.  There is an issue though.  When I tried to force a failover from the Secondary to the Primary using the dashboard I got a message stating that I needed to configure the WAN2 port and it would not let me switch.  I had to go in and unplug the cell device, force the failover and plug it back in.

Next I have to try

Primary WAN1 - ISP1

Primary WAN2 - ISP1

Secondary WAN1 - ISP1

Secondary WAN2 - ISP2 - we want this as a last resort