This read-write Boolean, indexed by a pair of security zone IDs, controls whether security logging is enabled for traffic flowing between that specific pair of zones, an "interzone." Since firewalls organize policy by zone pairs, this lets an admin turn on logging only for the interzone traffic they care about, such as untrust-to-trust, rather than logging every zone pair globally. For example, setting hwSLogEudmFlowEnableFlag to true for the entry indexed by zone 1 and zone 2 enables flow logging specifically for traffic crossing between those two zones.