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Cisco ASA 5500 Series Configuration Guide using the CLI
Chapter79 Configuring SNMP
Information About SNMP
You can configure the ASA to send traps, which are unsolicited messages from the managed device to
the management station for certain events (event notifications) to an NMS, or you can use the NMS to
browse the MIBs on the ASA. MIBs are a collection of definitions, and the ASA maintains a database
of values for each definition. Browsing a MIB means issuing a series of GET-NEXT or GET-BULK
requests of the MIB tree from the NMS to determine values.
The ASA has an SNMP agent that notifies designated management stations if events occur that are
predefined to require a notification, for example, when a link in the network goes up or down. The
notification it sends includes an SNMP OID, which identifies itself to the management stations. The
ASASNMP agent also replies when a management station asks for information.
Information About SNMP Terminology
Table79-1 lists the terms that are commonly used when working with SNMP:
Information About MIBs and Traps
MIBs are either standard or enterprise-specific. Standard MIBs are created by the IETF and documented
in various RFCs. A trap reports significant events occurring on a network device, most often errors or
failures. SNMP traps are defined in either standard or enterprise-specific MIBs. Standard traps are
created by the IETF and documented in various RFCs. SNMP traps are compiled into the ASA software.
If needed, you can also download RFCs, standard MIBs, and standard traps from the following locations:
http://www.ietf.org/
Table79-1 SNMP Terminology
Term Description
Agent The SNMP server running on the ASA. The SNMP agent has the following features:
•Responds to requests for information and actions from the network management station.
•Controls access to its Management Information Base, the collection of objects that the SNMP
manager can view or change.
•Does not allow set operations.
Browsing Monitoring the health of a device from the network management station by polling required information
from the SNMP agent on the device. This activity may include issuing a series of GET-NEXT or
GET-BULK requests of the MIB tree from the network management station to determine values.
Management
Information
Bases (MIBs)
Standardized data structures for collecting information about packets, connections, buffers, failovers, and
so on. MIBs are defined by the product, protocols, and hardware standards used by most network devices.
SNMP network management stations can browse MIBs and request specific data or events be sent as they
occur.
Network
management
stations (NMSs)
The PCs or workstations set up to monitor SNMP events and manage devices, such as the ASA.
Object identifier
(OID)
The system that identifies a device to its NMS and indicates to users the source of information monitored
and displayed.
Trap Predefined events that generate a message from the SNMP agent to the NMS. Events include alarm
conditions such as linkup, linkdown, coldstart, warmstart, authentication, or syslog messages.