Dedicated isolated out-of-band management interface

[dp]

I tried to search on this but got no leads. More and more equipment now comes with an out of band management interface. I know you can setup a third interface for management but unless it is isolated from the routing table somehow there are issues with routing on that interface and asymmetrical routing when trying to talk to that interface. Is there a way to create an interface that does not participate in the main routing of the firewall?

And yes I often miss things that are right in front of my face so if I did in this case please point me in that direction. This is going into main production next week and I am having to drink from the fire hose to learn it in time.

Thanks