Solaris

     in.ftpd  authenticates  users  according  to  the  following
     rules:

     First, the user name must be in the password data base,  the
     location  of  which  is  specified  in  nsswitch.conf(4). An
     encrypted password (an authentication token in PAM) must  be
     present.  A  password  must always be provided by the client
     before any  file  operations  can  be  performed.  For  non-
     anonymous  users,  the  PAM framework is used to verify that
     the correct password was entered. See SECURITY below.

     Second,  the  user  name  must  not  appear  in  either  the
     /etc/ftpusers  or  the  /etc/ftpd/ftpusers  file. Use of the
     /etc/ftpusers files is deprecated, although it is still sup-
     ported.

     Third, the users must have  a  standard  shell  returned  by
     getusershell(3C).

     Fourth, if the user name is anonymous or ftp,  an  anonymous
     ftp  account  must  be present in the password file for user
     ftp. Use ftpconfig(1M) to create the anonymous  ftp  account
     and home directory tree.

     Fifth, if the GSS-API is used to authenticate the user, then
     gss_auth_rules(5)  determines user access without a password
     needed.

     The FTP Server supports virtual hosting, which can  be  con-
     figured by using ftpaddhost(1M).

     The FTP Server does not support sublogins.