Local authentication validates that the user name and password that are entered with the logon match the ones that are stored in the system catalog.
The manager process that accepts the initial client connection is responsible for initiating the authentication checks and disallowing any future requests if the check fails. Because users can make connections across the network, the system sends passwords from clients in an opaque form.
The Netezza Performance Server system manages user names and passwords. It does not rely on the underlying (Linux®) operating system user name and password mechanism, other than on user nz, which runs the Netezza Performance Server software.