Cisco CCNA mock exam questions sample test – Question 271

.You have implemented SNMP v3 in your network. After making the configuration changes, you find that technicians in the TECHS group cannot access the MIB. You execute the
show run command and receive the following output that relates to SNMP:
What is preventing the TECHS group from viewing the MIB?

A. The presence of the keyword priv in the command creating the RESTRICTED group
B. A mismatch between the authentication mechanism and the encryption type in the command creating the TECHS user
C. The absence of an access list defining the stations that can used by the TECHS group
D. The presence of the keyword auth in the command creating the TECHS user

Correct Answer: C

Explanation:
The command that creates the TECHS group ends with the parameter access 99:
snmp-server group TECHS v3 priv read TECHS access 99
This indicates that the access list number 99 is specifying the IP addresses of the stations allowed to connect to the MIB for the group. Since the access list is missing from the
configuration, no IP addresses will be allowed, and no connections can be made by the group.
The presence of the keyword priv in the command creating the TECHS group is not causing the issue. This keyword indicates that encryption (privacy) and authentication should both
be used on all transmissions by the group.
In SMNPv3, there are three combinations of security that can be used:
noAuthNoPriv- no authentication and no encryption; includes the noauth keyword in the configuration
AuthNoPriv – messages are authenticated but not encrypted; includes the auth keyword in the configuration
AuthPriv – messages are authenticated and encrypted; includes the priv keyword in the configuration
There is no mismatch between the authentication mechanism and the encryption type in the command creating the TECHS user.
snmp-server user TECHS TECHS v3 auth sha CISCO priv des56 CISCO
In the preceding command, the section auth sha CISCO specified that messages are authenticated using SHA with a key of CISCO. It does not need to the match the section priv
des56 CISCO, which indicates that encryption (priv) will be provided using DES56 with a key of CISCO.
The presence of the keyword auth in the command creating the TECHS user is not causing the issue. This line indicates that that messages are authenticated using SHA with a key of
CISCO.
Objective:
Infrastructure Management
Sub-Objective:
Configure and verify device-monitoring protocols
References:
SNMP Configuration Guide, Cisco IOS XE Release 3SE (Catalyst 3850 Switches) > SNMPv3