SNMP Introduction
Basic command of SNMP:
- GET: The GET operation is a request sent by the manager to the managed device. It is performed to retrieve one or more values from the managed device.
- GET NEXT: This operation is similar to the GET. The significant difference is that the GET NEXT operation retrieves the value of the next OID in the MIB tree.
- GET BULK: The GETBULK operation is used to retrieve voluminous data from large MIB table.
- SET: This operation is used by the managers to modify or assign the value of the Managed device.
- TRAPS: Unlike the above commands which are initiated from the SNMP Manager, TRAPS are initiated by the Agents. It is a signal to the SNMP Manager by the Agent on the occurrence of an event.
- INFORM: This command is similar to the TRAP initiated by the Agent, additionally INFORM includes confirmation from the SNMP manager on receiving the message.
- RESPONSE: It is the command used to carry back the value(s) or signal of actions directed by the SNMP Manager.
- 1.3.6.1.2.1.1 - SNMP MIB-2 System
- 1.3.6.1.2.1.2 - SNMP MIB-2 Interfaces
- 1.3.6.1.2.1.3 - at
- 1.3.6.1.2.1.4 - ip
- 1.3.6.1.2.1.5 - icmp
- 1.3.6.1.2.1.6 - tcp
- 1.3.6.1.2.1.7 - udp
- 1.3.6.1.2.1.8 - egp
- 1.3.6.1.2.1.9 - cmot
- 1.3.6.1.2.1.10 - transmission
- 1.3.6.1.2.1.11 - snmp
- 1.3.6.1.2.1.14 - OSPF Version 2 MIB
- 1.3.6.1.2.1.15 - BGPv4
- 1.3.6.1.2.1.16 - Managed Objects for Bridges
- 1.3.6.1.2.1.17 - Bridge Mib
- 1.3.6.1.2.1.22 - rptrHealth
- 1.3.6.1.2.1.25 - HOST-RESOURCES-MIB, from RFC 1514
- 1.3.6.1.2.1.26 - Ethernet MAU mib
- 1.3.6.1.2.1.27 - Application MIB module
- 1.3.6.1.2.1.28 - MTA MIB module
- 1.3.6.1.2.1.29 - X.500 Directory MIB module
- 1.3.6.1.2.1.31 - ifMib
- 1.3.6.1.2.1.33 - upsMIB
- 1.3.6.1.2.1.34 - snaNode
- 1.3.6.1.2.1.38 - mdmMib
- 1.3.6.1.2.1.41 - sdlcStatus
- 1.3.6.1.2.1.43 - Printer-MIB
- 1.3.6.1.2.1.47 - entity-mib
- 1.3.6.1.2.1.69 - docsDev
- 1.3.6.1.2.1.92 - notificationLogMIB
OID:
This is a sample structure of OD:
Iso(1).org(3).dod(6).internet(1).private(4).transition(868).products(2).chassis(4).card(1).slotCps(2)-cpsSlotSummary(1).cpsModuleTable(1).cpsModuleEntry(1).cpsModuleModel(3).3562.3
or just:
1.3.6.1.4.868.2.4.1.2.1.1.1.3.3562.3
Private OID:
Many manufactures can supply custom MIB files for their hardware ,such as temperature , fan speed.
The MIB file is hard to read, they are only meant to be imported, or "compiled " by a Management Station.
Below is an example of Cisco MIB file for environment monitoring.
Cisco MIB information:
http://snmp.cloudapps.cisco.com/Support/SNMP/do/BrowseMIB.do?local=en&step=2
Load MIB file:
The files below is F5 MIB file.
We can use MIB Browser to load these file ,and you can see the F5 private OID in the picture.