The auth keyword specifies that the user should be authenticated using either the HMAC-MD5 or HMAC-SHA algorithms. These algorithms are specified during the creation of the SNMP user.

For example, the following command creates a user named V3User who will be a member of the SNMP group V3Group and will use HMAC-MD5 with a password of Password:

snmp-server user V3User V3Group v3 auth md5 Password

The authentication mechanism is not configured on the interface. All SNMP commands are executed at the global configuration prompt.

The authentication mechanism is not configured at the host level. The version and security model (authentication, authentication and encryption, or neither) are set at the host level.

The authentication mechanism is not configured at the SNMP group level. The group level is where access permissions like read and write are set. This is why a user account must be a member of a group to derive an access level, even if it is a group of one.