nats.docs/sys_accounts

System Events

NATS servers leverage Account support and generate events such as:

• account connect/disconnect
• authentication errors
• server shutdown
• server stat summary

In addition the server supports a limitted number of requests that can be used to query for account connections, server stat summaries, and pinging servers in the cluster.

These events are only accepted and visible to system account users.

The System Events Tutorial

You can learn more about System Accounts in the Tutorial.