I have an issue where I need to add a warm spare to an existing MX-250 configuration. I tried adding the spare into the dashboard via a Public IP I configured from the local dashboard on the standby MX250 via a laptop, I then added the serial and chose "Use uplink ips"  into the primary dashboard and it pretty much blew up my whole SD-Wan network this past weekend. I removed the spare and got things happy again pretty easily, but I'm stumped as to why I can't add the warm spare in at this point. The one caveat is that I don't have both WAN connections in the data center the standby was moved to only has one of the 2 WAN connections.  I have some questions after reading the willette documentation and Meraki...Assuming I can't use virtual IPs   They are both on the same hw/sw version (both mx250s) They are both plugged into the same Layer 2 switch on the single ISP side (/27 so plenty of spare IPs, I can see both Public IPS / MACs on the internet switch as well), so on my primary MX I have 2 wan interfaces, but on the warm spare I'd only have one. They are plugged into switch 1 and switch 2 of my core switch in a VSS pair - same vlan so LAN connectivity should be OK. Do I need to put a public IP on the spare MX - configured locally, and then add that in IP in via dashboard? I can't find a way to put an inside IP on the spare MX250 via the local dashboard? Does VRRP handle the LAN side? Meaning I don't add an IP on the LAN interface of the spare MX250 at all? Should I leave the LAN interface shutdown until it's added in via the Configure warm spare button? (like willette suggests) Thanks ... View more