CISCO CCNA Exam – Q223

Which three statements about the features of SNMPv2 and SNMPv3 are true? (Choose three.)

A. SNMPv3 enhanced SNMPv2 security features.
B. SNMPv3 added the Inform protocol message to SNMP.
C. SNMPv2 added the Inform protocol message to SNMP.
D. SNMPv3 added the GetBulk protocol messages to SNMP.
E. SNMPv2 added the GetBulk protocol message to SNMP.
F. SNMPv2 added the GetNext protocol message to SNMP.

Correct Answers: A, C, E

SNMPv1/v2 can neither authenticate the source of a management message nor provide encryption. Without authentication, it is possible for nonauthorized users to exercise SNMP network management functions. It is also possible for nonauthorized users to eavesdrop on management information as it passes from managed systems to the management system. Because of these deficiencies, many SNMPv1/v2 implementations are limited to simply a read-only capability, reducing their utility to that of a network monitor; no network control applications can be supported. To correct the security deficiencies of SNMPv1/v2, SNMPv3 was issued as a set of Proposed Standards in January 1998. -> A is correct.

The two additional messages are added in SNMP2 (compared to SNMPv1)
GetBulkRequest The GetBulkRequest message enables an SNMP manager to access large chunks of data. GetBulkRequest allows an agent to respond with as much information as will fit in the response PDU. Agents that cannot provide values for all variables in a list will send partial information. -> E is correct.

InformRequest The InformRequest message allows NMS stations to share trap information. (Traps are issued by SNMP agents when a device change occurs.) InformRequest messages are generally used between NMS stations, not between NMS stations and agents. -> C is correct.
Note: These two messages are carried over SNMPv3.

CISCO CCNA Exam – Q218

Which three features are added in SNMPv3 over SNMPv2?
A. Message Integrity
B. Compression
C. Authentication
D. Encryption
E. Error Detection

Correct Answers: A, C, D

Cisco IOS software supports the following versions of SNMP:
+ SNMPv1 – The Simple Network Management Protocol: A Full Internet Standard, defined in RFC 1157. (RFC 1157 replaces the earlier versions that were published as RFC 1067 and RFC 1098.) Security is based on community strings.

+ SNMPv2c – The community-string based Administrative Framework for SNMPv2. SNMPv2c (the “c” stands for “community”) is an Experimental Internet Protocol defined in RFC 1901, RFC 1905, and RFC 1906. SNMPv2c is an update of the protocol operations and data types of SNMPv2p (SNMPv2 Classic), and uses the community-based
security model of SNMPv1.

+ SNMPv3 – Version 3 of SNMP. SNMPv3 is an interoperable standards-based protocol defined in RFCs 2273 to 2275. SNMPv3 provides secure access to devices by a combination of authenticating and encrypting packets over the network. The security features provided in SNMPv3 are as follows:

– Message integrity: Ensuring that a packet has not been tampered with in transit.
– Authentication: Determining that the message is from a valid source.
– Encryption: Scrambling the contents of a packet prevent it from being learned by an unauthorized source.