Probleme listener 12518 / 12564

[genio]

Bonjour les forumistes (Oracle 9i)...
j'ai un problème de connection entre deux machines Unix ...
Voici le sqlnet.log :

Fatal NI connect error 12518, connecting to:
(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=1.999.222.1)(PORT=4009))(CONNECT_DATA=(SERVICE_NAME=toto)(CID=(PROGRAM=)(HOST= HOSTTOTO)(USER=oracle))))

VERSION INFORMATION:
TNS for IBM/AIX RISC System/6000: Version 9.2.0.4.0 - Production
TCP/IP NT Protocol Adapter for IBM/AIX RISC System/6000: Version 9.2.0.4.0 - Production
Time: 12-JUL-2006 14:37:29
Tracing not turned on.
Tns error struct:
nr err code: 0
ns main err code: 12564
TNS-12564: TNS:connection refused
ns secondary err code: 0
nt main err code: 0
nt secondary err code: 0
nt OS err code: 0

Pouvez-vous m'aider ?

PS : La base est ouverte et accessible via sqlplus...

[genio]

Quelqu'un peut-il m'aider ?

PS : Quand je fais un tnsping sur l'instance, le tnsname la reconnait bien ...


<serveur - unix> /u01/app/oracle/product/9.2.0/ # tnsping Mabase

Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 9.999.9.999)(PORT = 4009))) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = Mabase)))
OK (0 msec)