SNMP

Question 1

T/F: SNMP can be used to make configuration changes

Answer 1

T

Question 2

What are the two main types of devices in SNMP

Answer 2

1) Managed Devices (switches, routers)
2) Network Management Stations (NMS)

Question 3

What are the 3 main functionalities provided by SNMP

Answer 3

1) Managed devices notify NMS of events (failures, restoration, etc)
2) NMS can ask managed devices for their status
3) NMS instructs managed devices to make a config change

Question 4

What are the two components of the NMS’s SNMP software

Answer 4

1) SNMP Manager, interacts with managed devices
2) SNMP Application, provides UI for admins

Question 5

What is the function of an NMS’s SNMP Manager component

Answer 5

To interact with managed devices. Receives notifications, sends requests for information, sends config changes, etc.

Question 6

What is the function of an NMS’s SNMP Application component

Answer 6

To provide a UI for a sysadmin to interact with. Displays alters, statistics, charts, etc

Question 7

What are the two components of a Managed Device’s SNMP software

Answer 7

1) SNMP Agent
2) Management Information Base (MIB)

Question 8

What is the function of a Managed Device’s SNMP Agent

Answer 8

To interact with the SNMP manager on the NMS. Send notifications, receive config change orders, etc.

Question 9

What is a Managed Device’s Management Information Base (MIB)

Answer 9

The structure that contains the variables that are managed/reported by SNMP

Question 10

T/F: each variable in the MIB is identified by an Object ID (OID)

Answer 10

True

Question 11

How are SNMP OIDs organized

Answer 11

A hierarchical structure.

Essentially works by organizing variables in sub directories, and each number represents a level.

For example -> 1.3.6.1.2.1.1.5 ::

– iso
– identified-organization
– dod
– internet
– mgmt
– mib-2
– system
– sysName

This variable would give you the hostname for a cisco device, if a NMS requested this OID

Question 12

What are the 3 major versions of SNMP that achieved widespread use

Answer 12

v1
v2c
v3

Question 13

What is the version of SNMP widely in use today

Answer 13

v3

Question 14

What are the classes of SNMP messages

Answer 14

Read
Write
Notification
Response

Question 15

What is the well known listening port for an SNMP trap

Answer 15

UDP 162

Question 16

What does a Cisco device use to respond to GET requests

Answer 16

SNMP agent

Question 17

What is a benefit of using SNMPv3 instead of v2

Answer 17

Encryption and authentication between devices

Question 18

What is the benefit of using the correct MIB with a Cisco router

Answer 18

Ensures you have correct SNMP operations. Each different device can have different MIBs, so you have to configure your SNMP manager to read correctly

Question 19

What is the well known listening port for SNMP agents

Answer 19

UDP 161

Question 20

What type of SNMP request is used by the manager to configure an SNMP managed device

Answer 20

Set

Question 21

What are the sub-types of the SNMP read message class

Answer 21

Get
GetNext
GetBulk

Question 22

Explain the difference between the Get, GetNext, and GetBulk read message types

Answer 22

“Get” retrieves the value of one or more OIDs. Agent will send a Response message with current value for each variable

“GetNext” requests available variables in the managed device’s MIB

“GetBulk” is a more efficient version of the GetNext message, was introduced in SNMPv2

Question 23

What are the sub-types of the SNMP write message class

Answer 23

There is only 1:

Set

Question 24

Explain what the Set write message type does

Answer 24

Request sent from manager to an agent to change the value of one or more variables. Agent will send a Response class message with the new values

Question 25

What are the sub-types of the SNMP notification message class

Answer 25

Trap
Inform

Question 26

Explain what the Trap message type does

Answer 26

A notification sent from the agent to the manager. The manager doesn’t send a Response message to acknowledge it received the Trap, so this is considered an unreliable message

Question 27

Explain what the Inform message type does

Answer 27

A notification that is acknowledged with a Response message. Can be sent/received by either the manager or the managed device

Question 28

What are the sub-types of the SNMP response message class

Answer 28

Just one, response

Question 29

Explain what the Response message type does

Answer 29

Message sent in response to a previous message/request, essentially an acknowledgement message

Question 30

Does SNMP use TCP or UDP for communications?

Answer 30

UDP