TRIGGER AFTER LOGON

CREATE OR REPLACE TRIGGER LOG_T_LOGON
AFTER LOGON ON DATABASE
DECLARE
    osUser VARCHAR2(30);
    machine VARCHAR2(100); 
    prog VARCHAR2(100);
    ip_user VARCHAR2(15);
BEGIN
    SELECT OSUSER, MACHINE, PROGRAM, ora_client_ip_address
    INTO osUser, machine, prog, ip_user
    FROM v$session
    WHERE SID = SYS_CONTEXT('USERENV', 'SID');

    IF (osUser = 'APuente' AND prog = 'SQL Developer')THEN
        RAISE_APPLICATION_ERROR(-20000,'Denied!  You are not allowed to logon from host '||prog|| ' using '|| osUser);
    END IF;
END;
/