Configuring SNMP Subagent

SNMP is a protocol used to exchange data about network activity. With SNMP, data travels between a managed device and a network management station (NMS). A managed device is anything that runs SNMP: hosts, routers, your web server, and other servers on your network. The NMS is a machine used to remotely manage that network. Usually, the NMS software will provide a graph to display collected data or use that data to make sure the server is operating within a particular tolerance.

The NMS is usually a powerful workstation with one or more network management applications installed. A network management application such as HP OpenView graphically shows information about managed devices, such as your web servers. For example, it might show which servers in your enterprise are up or down, or the number and type of error messages received. When you use SNMP with a Sun Java System Web Server, this information is transferred between the NMS and the server through the use of two types of agents, the subagent and the master agent.

The subagent gathers information about the server and passes the information to the server's master agent.

For starting the SNMP subagent, perform the following tasks:

Click Nodes tab
Click available node from the nodes list.
Click SNMP Subagent tab
Click Start SNMP Subagent button to start the subagent.

Note - Before starting the SNMP subagent, verify that the master agent is running. The subagent is started only when the master agent is running.

For stopping the SNMP subagent, perform the following tasks:

Click Nodes tab
Click available node from the nodes list.
Click SNMP Subagent tab
Click Stop SNMP Subagent button to stop the subagent.

In general, to use SNMP you must have a master agent and at least one subagent installed and running on a your system. You need to install the master agent before you can enable a subagent.

The procedures for setting up SNMP are different depending upon your system. The following table provides an overview of procedures you will follow for different situations. The actual procedures are described in detail later in the chapter.

Before you begin, you should verify two things:

Is your system already running an SNMP agent (an agent native to your operating system)?
If so, does your native SNMP agent support SMUX communication? (If you're using the AIX platform, your system supports SMUX.)

See your system documentation for information on how to verify this information.

Note - After changing SNMP settings in the Administration Server, for installing a new server, or deleting an existing server, you must perform the following steps:

(Windows) Restart the Windows SNMP service or reboot the machine.
(UNIX) Restart the SNMP master agent using the Administration Server.

Table 3 Procedure for working with SNMP

If your server meets these conditions	Follow these procedures
No native agent is currently running	Start the master agent. Enable the subagent for each server installed on the system.
Native agent is currently running No SMUX No need to continue using native agent	Stop the native agent when you install the master agent for your Administration Server. Start the master agent. Enable the subagent for each server installed on the system.
Native agent is currently running No SMUX Needs to continue using native agent	Install a proxy SNMP agent. Start the master agent. Start the proxy SNMP agent. Restart the native agent using a port number other than the master agent port number. Enable the subagent for each server installed on the system.
Native agent is currently running SMUX supported	Reconfigure the SNMP native agent. Enable the subagent for each server installed on the system.

For more information on setting up a master agent, see Sun Java System Administrator's Guide