This parameter has been deprecated since Samba 4.13 and support for plaintext (as distinct from NTLM, NTLMv2 or Kerberos authentication) will be removed in a future Samba release. That is, in the future, the current default of client plaintext auth = no will be the enforced behaviour. Specifies whether a client should send a plaintext password if the server does not support encrypted passwords. no