Cli And Snmp User Synchronization - Cisco Nexus 9000 Series Configuration Manual

Configuring SNMP
• Message integrity—Ensures that messages have not been altered or destroyed in an unauthorized manner
and that data sequences have not been altered to an extent greater than can occur nonmaliciously.
• Message origin authentication—Ensures that the claimed identity of the user on whose behalf received
data was originated is confirmed.
• Message confidentiality—Ensures that information is not made available or disclosed to unauthorized
individuals, entities, or processes.
SNMPv3 authorizes management operations only by configured users and encrypts SNMP messages.
Cisco NX-OS uses two authentication protocols for SNMPv3:
• HMAC-MD5-96 authentication protocol
• HMAC-SHA-96 authentication protocol
Cisco NX-OS uses Advanced Encryption Standard (AES) as one of the privacy protocols for SNMPv3 message
encryption and conforms with RFC 3826.
The priv option offers a choice of DES or 128-bit AES encryption for SNMP security encryption. The priv
option and the aes-128 token indicate that this privacy password is for generating a 128-bit AES key. The
AES priv password can have a minimum of eight characters. If the passphrases are specified in clear text, you
can specify a maximum of 64 case-sensitive, alphanumeric characters. If you use the localized key, you can
specify a maximum of 130 characters.
Note For an SNMPv3 operation using the external AAA server, you must use AES for the privacy protocol in
the user configuration on the external AAA server.

CLI and SNMP User Synchronization

SNMPv3 user management can be centralized at the Access Authentication and Accounting (AAA) server
level. This centralized user management allows the SNMP agent in Cisco NX-OS to leverage the user
authentication service of the AAA server. Once user authentication is verified, the SNMP PDUs are processed
further. Additionally, the AAA server is also used to store user group names. SNMP uses the group names to
apply the access/role policy that is locally available in the switch.
Any configuration changes made to the user group, role, or password results in database synchronization for
both SNMP and AAA.
Cisco NX-OS synchronizes the user configuration in the following ways:
• The authentication passphrase specified in the snmp-server user command becomes the password for
the CLI user.
• The password specified in the username command becomes the authentication and privacy passphrases
for the SNMP user.
• If you create or delete a user using either SNMP or the CLI, the user is created or deleted for both SNMP
and the CLI.
• User-role mapping changes are synchronized in SNMP and the CLI.
• Role changes (deletions or modifications) from the CLI are synchronized to SNMP.
Cisco Nexus 9000 Series NX-OS System Management Configuration Guide, Release 6.x
SNMPv3
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