This policy setting determines the permitted list of hosts that can submit a query to the Simple Network Management (SNMP) agent running on the client computer.
Simple Network Management Protocol is a protocol designed to give a user the capability to remotely manage a computer network by polling and setting terminal values and monitoring network events.
The manager is located on the host computer on the network. The manager's role is to poll the agents for certain requested information.
If you enable this policy setting, the SNMP agent only accepts requests from the list of permitted managers that you configure using this setting.
If you disable or do not configure this policy setting, SNMP service takes the permitted managers configured on the local computer instead.
Best practice: For security purposes, it is recommended to restrict the HKLM\SOFTWARE\Policies\SNMP\Parameters\PermittedManagers key to allow only the local admin group full control.
Note: This policy setting has no effect if the SNMP agent is not installed on the client computer.
Also, see the other two SNMP policy settings: "Specify trap configuration" and "Specify Community Name".