Remote external procedure call ORA-28576

Question

Hi,
I have to call an external procedure (c program) which is in another(remote) host system.
I have created a simple c program and when i call it from the same database host (Oracle 11.2.0.3 in linux 2.6.39) every thing work fine, but when i call it from another database found in a remote host (Oracle 11.2.0.3 HP-UX 11iv3) i receive these error "ORA-28576". The "extproc" program was started by the listener (i can see that in the listener logfile) but then the connection was aborted.
So my question is can i call remote external proc program from a remote host ? if yes how can i do that ? thanks for help
Configuration :
listener.ora
LISTENER =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = MYHOST)(PORT = 1521))
SID_LIST_LISTENER =
    (SID_LIST=
        (SID_DESC= (SID_NAME=callout)
        (ORACLE_HOME=/app/oracle/11.2.0.3)
        (ENVS = 'EXTPROC_DLLS=/tmp/test.so')
        (PROGRAM=extproc)
tnsnames.ora
extproc_connection_data =
   (DESCRIPTION =
       (ADDRESS = (PROTOCOL=tcp)(host=MYHOST)(port=1521))
       (CONNECT_DATA=(SID=callout))
test.c
#include <stdio.h>
int square(int x)
return((x*x) + 1); //adds 1 to the return value
PL/SQL code
CREATE DATABASE LINK agent_link USING 'extproc_connection_data';
CREATE OR REPLACE LIBRARY test_lib IS '/tmp/test.so' AGENT 'agent_link';
CREATE OR REPLACE FUNCTION test_proc (X BINARY_INTEGER) RETURN BINARY_INTEGER
AS
EXTERNAL LIBRARY test_lib
NAME "square"
LANGUAGE C;
CREATE OR REPLACE PROCEDURE EXTPROCTEST (X BINARY_INTEGER)
AS
   RetValue   BINARY_INTEGER;
BEGIN
   RetValue := test_proc (X);
   DBMS_OUTPUT.PUT_LINE (RetValue);
END;
SET SERVEROUTPUT ON
EXECUTE EXTPROCTEST(10);

Answer 1

Hi,
I found the answare, it seem that for security reason the listener,extproc agent and the instance must be on the same host.
Reference : (http://docs.oracle.com/cd/E11882_01/appdev.112/e10825/pc_07pls.htm#sthref1051)
>
The database server, the agent process, and the listener process that spawns the agent process must all reside on the same host.
>
>
For security reasons, extproc, by default, loads only DLLs that are in directory $ORACLE_HOME/bin or $ORACLE_HOME/lib. Also, only local sessions—that is, Oracle Database client processes that run on the same system—are allowed to connect to extproc.