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You can use Simple Network Management Protocol (SNMP) to monitor a WebLogic Server domain. This page summarizes the SNMP agents that have been configured for the current WebLogic Server domain.
With SNMP, you configure agents to gather and send data about managed resources in response to a request from managers. You can also configure agents to issue unsolicited reports to managers when they detect predefined thresholds or conditions on a managed resource.
In a WebLogic Server domain, you can choose a centralized or de-centralized model for SNMP monitoring and communication:
- In a centralized model, you configure an SNMP agent only on the Administration Server. This agent communicates with all Managed Servers in the domain. Your SNMP manager communicates only with the SNMP agent on the Administration Server. This model is convenient but introduces performance overhead in WebLogic Server. In addition, if the Administration Server is unavailable, you cannot monitor the domain through SNMP.
- In a de-centralized model, you configure SNMP agents on each Managed Server. Your SNMP manager must communicate with the agents on individual Managed Servers.
To support domains that were created with WebLogic Server release 9.2 and earlier, you can enable and use the domain-scoped SNMP agent instead of configuring SNMP agents on the Administration Server or Managed Servers (server SNMP agents). The domain-scoped agent offers the same features as the server SNMP agent in the centralized model described above. However, its underlying implementation is different and it will eventually be deprecated. The domain-scoped agent is overridden if you target a server SNMP agent to the Administration Server.
You can show fewer or additional data points on this page by expanding Customize this table and modifying the Column Display list. Each data point displays in its own table column.
The following table lists all of the data points that you can display in columns on this page.
Name Description Name
The alphanumeric name for this SNMP agent.
For a server SNMP agent, you assign this name when you create the agent. For the domain-scoped SNMP agent, the name always matches the name of the domain.
Specifies whether this SNMP agent is enabled.
The SNMP notification version that this SNMP agent generates.
Send Automatic Traps Enabled
Specifies whether this SNMP agent sends automatically generated notifications to SNMP managers.
The SNMP agent generates automatic notifications when any of the following events occur:
The WebLogic Server instance that is hosting the SNMP agent starts.
This type of notification (coldStart) has no variable bindings.
A server instance starts or stops.
An SNMP agent on a Managed Server generates these notifications only when its host Managed Server starts or stops. An SNMP agent on an Administration Server generates these notifications when any server in the domain starts or stops.
These notification types (serverStart and serverShutdown) contain variable bindings to identify the server that started or stopped and the time at which the notification was generated.
The port on which you want this SNMP agent to listen for incoming requests from SNMP managers that use the UDP protocol.
SNMP managers can use this port to ping the SNMP agent and request the status of specific attributes.
If you target this SNMP agent to multiple server instances, and if two or more servers are running on the same computer, WebLogic Server will automatically increment this UDP port value by 1 for each agent. WebLogic Server never assigns port 162 because it is the default port that an agent uses to send notifications. In addition, if any port is already in use, WebLogic Server skips the port and assigns the next available port.
For example, if you use the default value of this attribute and then target this agent to ManagedServer1 and ManagedServer2, and if both servers are running on the same computer, then the agent on ManagedServer1 will listen on UDP port 161 and the agent on ManagedServer2 will listen on UDP port 163.
The incremented port number is not persisted in the domain's configuration; when WebLogic Server increments port numbers, it does so in the order in which servers are started on the same computer.
If WebLogic Server re-assigns the UDP port for an SNMP agent, look in the agent's SNMPAgentRuntimeMBean to see the agent's runtime UDP port.
SNMP agents can also communicate through the host server's TCP listen port (7001 by default) or through a TCP port that is configured by a custom network channel.
The password (community name) that you want this SNMP agent to use to secure SNMPv1 or v2 communication with SNMP managers. Requires you to enable community based access for this agent.
SNMPv3 does not use community names. Instead, it encrypts user names and passwords in its PDUs.
When you use SNMPv1 or v2, there are two community names that are needed when the WebLogic SNMP agent and SNMP managers interact:
The name that you specify in this community prefix. All SNMP managers must send this name when connecting to this SNMP agent.
The community name that the SNMP manager defines. The SNMP agent must send this name when connecting to the manager. (You supply this community name when you configure a trap destination.)
In addition to using the community prefix as a password, an SNMP agent on an Administration Server uses the prefix to qualify requests from SNMP managers. Because the Administration Server can access data for all WebLogic Server instances in a domain, a request that specifies only an attribute name is potentially ambiguous. For example, the attribute
serverUptimeexists for each WebLogic Server instance in a domain. To clarify requests that you send to SNMP agents on Administration Servers, use the community prefix as follows:
To request the value of an attribute on a specific Managed Server, when you send a request from an SNMP manager, append the name of the server instance to the community prefix:
To request the value of an attribute for all server instances in a domain, send a community name with the following form:
To secure access to the values of the WebLogic attributes when using the SNMPv1 or v2 protocols, it is recommended that you set community prefix to a value other than
You cannot specify a null (empty) value for the community prefix. If you delete the prefix value, WebLogic Server resets the value to
public. If you do not want this agent to receive SNMPv1 or v2 requests, instead of trying to set the community prefix to a null value, disable community based access. With community based access disabled, WebLogic Server ignores the community prefix value.
The minimum severity of debug messages that this SNMP agent generates.
The SNMP agent writes all debug messages to standard out; they are not written to the WebLogic Server log files. Debug messages provide a detailed description of the SNMP agent's actions. For example, the agent outputs a noncritical message each time it generates a notification.
Valid values are:
No debug messages.
Fatal messages only.
Critical and fatal messages.
Non-critical, critical, and, fatal messages.
Community Based Access Enabled
Specifies whether this SNMP agent supports SNMPv1 and v2.
SNMPv1 and v2 use community strings for authentication. If you disable community strings for this SNMP agent, the agent will process only SNMPv3 requests. If an SNMP manager sends a v1 or v2 message, the agent discards the message and returns an error code to the manager.
An identifier for this SNMP agent that is unique amongst all other SNMP agents in the current WebLogic Server domain.
If you use SNMPv3 to send messages to this SNMP agent, you must specify the SNMP engine ID when you configure the SNMP manager.
For an SNMP agent on an Administration Server, the default value is the name of the WebLogic Server domain. For an agent on a Managed Server, the default is the name of the server.
The protocol that this SNMP agent uses to ensure that only authorized users can request or receive information about your WebLogic Server domain. Applicable only with SNMPv3.
The protocol also ensures message integrity and prevents masquerading and reordered, delayed, or replayed messages.
To use this protocol when receiving requests from SNMP managers, you must configure credential mapping in the WebLogic Server security realm. To use this protocol when sending responses or notifications, you must configure the security level of your trap destinations.
If you do not choose an authentication protocol, then the SNMP agent does not authenticate incoming SNMPv3 requests; anyone can use SNMPv3 to retrieve information about your WebLogic Server domain.
The protocol that this SNMP agent uses to encrypt and unencrypt messages. Applicable only with SNMPv3. Requires you to also use an authentication protocol.
To use this protocol when sending responses or notifications, you must also configure the security level of your trap destinations.
If you do not choose a privacy protocol, then communication between this agent and managers can be viewed (but not altered) by unauthorized users.
Inform Retry Interval
The number of milliseconds that this SNMP agent will wait for a response to an INFORM notification.
If the agent does not receive a response within the specified interval, it will resend the notification.
Credential Cache Invalidation Interval
The number of milliseconds after which WebLogic Server invalidates its cache of SNMP security keys. Setting a high value creates a risk that users whose credentials have been removed can still access SNMP data.
An SNMP security key is an encrypted version of an SNMP agent's engine ID and an authentication password or privacy password. WebLogic Server generates one security key for each entry that you create in the SNMP credential map. When a WebLogic Server SNMP agent receives an SNMPv3 request, it compares the key that is in the request with its WebLogic Server keys. If it finds a match, it processes the request. The SNMP agent also encodes these keys in its responses and notifications. (You configure which keys are encoded when you create a trap destination.)
Instead of regenerating the keys for each SNMPv3 communication, WebLogic Server caches the keys. To make sure that the cache contains the latest set of SNMP credentials, WebLogic Server periodically invalidates the cache. After the cache is invalidated, the next time an SNMP agent requests credentials, WebLogic Server regenerates the cache.
Note that making a change to the credential map does not automatically update the cache. Instead, the cache is updated only after it has been invalidated.
For example, if you update a privacy password in an existing entry in the SNMP credential map, the SNMP agent is not aware of the new password until the key cache is invalidated and regenerated. An SNMP user with the old security password can still access WebLogic Server data until the cache is invalidated.
You can invalidate a key immediately instead of waiting for this invalidation interval to expire.
Maximum Inform Retry Count
The maximum number of times that this SNMP agent will resend INFORM notifications for which it has not received a response.
- WebLogic SNMP Management Guide
- WebLogic SNMP MIB Reference