[CentOS] How to block routing/forwarding with firewalld

[Kenneth Porter]

--On Tuesday, July 12, 2016 11:20 AM -0700 Jeff White <jeff.white at wsu.edu> 
wrote:

> how do you tell firewalld to stop forwarding traffic between interfaces?

(Caveat: I'm a firewalld virgin so know only what I've read.)

I believe firewalld works in terms of "zones", not interfaces. An interface 
belongs to a zone. So you need to create new zones that contain each 
interface you want to isolate, based on the default zone properties. You 
can then issue rules based on those zones.