Template:FAQ:Agent 23b

Although an SNMP agent may support a wide range of management information, it is not necessarily appropriate to report the whole of this to every SNMP management station who asks for it. Some information may be sensitive, and should restricted to authorized administrators only. SNMP therefore includes mechanisms for controlling who has access to what information - both in terms of what can be seen, and (even more importantly) what can be changed.

By default, the Net-SNMP agent starts up with a completely empty access control configuration. This means that no SNMP request would be successful. It is necessary to explicitly configure suitable access control settings, based on who should be granted access in that particular environment.

If there are no access control entries configured (perhaps because no snmpd.conf configuration file has been loaded, or it contains no access control settings), then the agent will not respond to any SNMP requests whatsoever. This is almost certainly not what was intended, so the agent reports this situation.

See the next entry for how to configure access control settings.