Last Updated on August 1, 2021 by Admin 1
You have implemented SNMP v3 in your network. You find after making the configuration changes that technicians in the RESTRICTED group cannot access the MIB. You execute the show run command and receive the following output that relates to SNMP:
What is preventing the RESTRICTED group from viewing the MIB?
- the presence of the keyword priv in the command creating the RESTRICTED group
- a mismatch between the authentication mechanism and the encryption type in the command creating the RESTRICTED user
- the absence of an access list defining the stations that can used by the RESTRICTED group
- the presence of the keyword auth in the command creating the RESTRICTED user
At the end of the command creating the RESTRICTED group is the parameter access 99. This indicates that an access list number 99 is being used to specify the allowed IP addresses of the stations that can be used 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 RESTRICTED 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 noauth keyword in the configuration
AuthNoPriv – messages are authenticated but not encrypted auth keyword in the configuration
AuthPriv – messages are authenticated and encrypted priv keyword in the configuration
There is no mismatch between the authentication mechanism and the encryption type in the command creating the RESTRICTED user.
snmp-server user RESTRICTED RESTRICTED 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 RESTRICTED user is not causing the issue. This line indicates that that messages are authenticated using SHA with a key of CISCO.
Objective:
Infrastructure Services
Sub-Objective:
Configure and verify SNMP