ZBXNEXT-747 handles traps for specific interfaces. However, if a trap comes in from an unknown host, it can only be logged. There should be a global handling system for such traps.

There are several options how to implement this:
1) Fallback interface. "Forward" all unmatched traps to a fallback interface (unique for the whole system or each proxy/server) and parse it similarly as for any other interface.
2) Auto-registration for unknown traps. Create new hosts with SNMP interfaces for unmatched traps.
3) Create internal items for unmatched traps.