I've been doing some discovery runs on IP domain containing SNMP-compliant nodes such as network printers, but the discovery results always came up as 'Unknown.' I set Wireshark to monitoring on the ZCM 10.3 server as I had it run another SNMP-based discovery, and though I saw some pings, not a single SNMP packet went across the wire. What the heck?

Net-SNMP is indeed installed, the server firewall is OFF, and running SNMPWALK from the server against one of the nodes in question results in good data. Someone toss me a clue?