How does agentless monitoring differ from agent-based monitoring?

Agentless monitoring *can* access data via API, but agent-based monitoring is not necessarily 'less efficient'; agents can be highly optimized for local data collection and processing.

Agent-based monitoring allows the agent software to process and filter log data directly on the host, potentially making its data collection less intrusive in terms of network bandwidth and allowing it to integrate deeply with the OS. Conversely, agentless monitoring relies on remote polling via standard protocols (like WMI, SNMP, SSH), which necessitates having specific network ports open on the target systems for the monitoring system to establish connections.

Agent-based monitoring usually has *higher* initial deployment costs due to agent installation and management, whereas agentless can have lower initial costs if existing protocols are utilized.

Agent-based monitoring *does* have the capability to locally filter and transmit only valuable data, which is a key advantage, making the statement that agentless has this ability incorrect or misleading.