SNMP VEQSIONS
VEQSION 1
VEQSION 2
VEQSION 3
SNMP VI - The Least Secure version of
SNMP Protocol due to its lack of encryption. sending
passwords over Plain Text
SNMP v2 - Large improvements in over the first version,
including transport mappings, MIB Structure elements
and most importantly, improved authentication and
security updates.
SNMP v3 - Implemented "User-Based
Security". This security feature allows you to
set Authentication/Encryption based on the
user requirements. The 3 levels of auth.
are: NoAuthNoPriv, AuthNoPriv and Authpriv.
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.
cclTT(01
DIRECTORY (1)
wa.2(1)
SYSTEM
MIB Tree Diagram
MIB
The Registered Tree
Root
MEMBER BODY
AUTHORITY
AUSTRALIA
EXPERIMENTAL
PRIVATE
JOINT Iso.cclTr12?
ORGANIZATION (3)
DOD
INTERNET
SNMP
(2)
org (3)
dod (6)
Internet (l )
experime
directory (I)
rWb-2 (1)
interfaces (2)
private (4)
enterprise (1)
microsoft
systn (I)
ip (4)
Cisco (9)
(311)
juniperMIB
(2636
OID Tree Example
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.
计算机生成了可选文字:
S 2 iOOCISCOEnVMonVO ItagestatusEntry
0 日 ] ECT —TY P E 囗
SYNTAX
M × 一 C 匚 E 5 5 not—accessibleO
STAT 凵 5
C 凵 r r e nt 囗
凵 苁 n entry n the voltage S t at 凵 S
D E 5 匚 R I PT 10 N 囗
t 彐 匕 ] e , representing the S t at 凵 S 囗
Of the associated
testpoint maintained 匕 the environmentalO
{ CiSCOEnVMonV01tageStatuSIndex } 囗
m 囗 n ] t 囗 r 。
I N D EX
{ CiSCOEnVMonV01tageStatuSTab1e 1 } 囗 囗
SEQUENCE { 囗
Integer32 ( 0 . . 214 74 8 54 7 〕 , 囗
Displ aystring , 囗
dl_OW I e g e r 2 , 囗
ciscoEnVMonVOltageThresholdHigh I nt e g e r 2 ,
CiSCOEnVMonV01tageLaStShutdown I e g e r 2 , 囗
CiSCOEnVMonV01tageState
匚 ] S C 囗 E 囗 n St
CiSCOEnVMonV01tageStatuSIndex 0 日 ] ECT —TY P E 囗
SYNTAX
Integer32 ( 0 . . 21474H 547 〕 囗
STAT 凵 5
C 凵 r r e nt 囗
M × 一 C 匚 E 5 5 not—accessibleO
D E 5 匚 R I PT 10 N 囗
index for the testpoint being
This index S for 5 NM P purposes 囗 n ] , and has n 囗 囗
] nt r ] n S ] C m e 彐 n ] n 0 。 凵 囗