communicate with another private port.
All unicast/broadcast/multicast layer2 traffic is blocked so it works much the
same way as using firewall rules but scales better and is generally easier as
firewall packages usually do not allow ARP blocking.
An example usage would be having a number of customers on separate vlans
bridged with a server network. All the vlans are marked private, they can all
communicate with the server network unhindered, but can not exchange any
traffic whatsoever with each other.
Approved by: re (rwatson)
aa0911f204