WebLogic SNMP Management Guide

Understanding SNMP Proxies

The following sections provide background information on WebLogic Server and SNMP proxy agents. For information on configuring WebLogic Server to be a proxy for other SNMP agents, refer to "Create SNMP Proxies" in the Administration Console Online Help.

SNMP Agent as Proxy for Other Agents

The original SNMP management model allowed for only a single, monolithic agent to carry out all management responsibilities on a given network node (IP address). This solution was not flexible enough to enable effective management of increasingly complex systems. In addition to the agents typically provided by computer manufacturers for hardware and operating system information, agents are also produced by vendors of other products, such as agents for SQL database systems. Complex and heterogeneous systems thus require the ability to accommodate multiple agents on a single network node.

This weakness of the original SNMP model led to the concept of an SNMP master agent that acts as a proxy for other SNMP agents. The WebLogic SNMP agent can function as a master agent in this sense. To use the master agent functionality of the WebLogic SNMP agent, you can assign branches of the registration tree (OID tree) as the responsibility of other (non-Weblogic) SNMP agents. Each of these will be a branch that encompasses the private MIB (or some part of that MIB) that the target agent is designed to manage.

Note: You cannot use the WebLogic SNMP agent as a proxy for SNMP agents in other WebLogic Server domains. For example, WebLogic domainA's SNMP agent cannot proxy requests to domainB's SNMP agent. This limitation is in effect because all WebLogic SNMP agents use the same MIB root.

Instead of proxying requests to multiple WebLogic Server domains, you can place all of your server instances in a single domain and send requests directly to each Managed Server. See Using Community Names to Specify Target Servers in Management Requests.

The WebLogic SNMP agent listens for requests from SNMP managers and then fans out these requests to other SNMP agents on the Administration Server machine, if the attribute requested has an OID falling under the branch of the OID tree assigned to one of those other agents. By default the WebLogic SNMP agent listens for management requests on port 161. If the WebLogic SNMP agent is to proxy for other SNMP agents, then those other agents must be configured to listen for SNMP management requests on a port other than the port that the WebLogic SNMP agent is using to receive requests from SNMP managers. For information on configuring the WebLogic Server SNMP agent, see Configure the SNMP Agent in the Administration Console Online Help.

The Microsoft Windows SNMP Service

While the WebLogic Server SNMP agent can be a proxy for other SNMP agents, it cannot be configured as a subagent of the Microsoft Windows SNMP agent service.

Using Microsoft Extension Agent API, the Microsoft Windows 2000 SNMP agent service can be a proxy for other SNMP agents. However, WebLogic Server does not support this feature and cannot use the Windows SNMP agent as a proxy.