Unless you suppressed their prompting, you must normally supply a username and password when logging on to a DP4 database through the ODBC interface. These are validated against the username list, set up on the system database.
To allow users to log on to a DP4 database anonymously, with a blank user name and password, you can add the line:
anon_logon_ok = 1
to the appropriate [<DP4_data_source>] section of the ODBC.INI file. (This does not stop the system prompting for a user name and password - to stop this, refer to step 4 in Adding Data Sources). If you do this ODBC connections will have unrestricted access to the database without supplying any login credentials.