I've been testing passive network discovery via proxy/zones and so far is working quite well.
However, when it detects a node that has neither an agent on it nor SNMP enabled to query for the hostname, it adds the node just by the IP address.
I can see in the logs that it is trying to resolve the IP to a hostname, but this appears to happen on the NetXMS server itself, not the proxy node of the zone through which the discovery happened?
This can lead to a rather large amount of not too useful nodes ending up in the system.

For now I just wrote a hook that basically sets anything to unmanaged that has neither an agent nor SNMP and ignore those systems.
But it would be nice for mapping purposes, if they would show with their correct hostnames as per local DNS.

Cheers