Re: My TNS listener stopped working

I am confused by the symptoms you describe. The "ORA-12543: TNS:destination host unreachable" indicates that the client can not find the host on the network. Yet, you say that a TNSPING replies "OK". For the TNSPING to work, the client had to reach the listener and get a positive respone from the listener. As far as I know, this doesn't say anything about the state of the database, just that the listener is available and listening for the SID indicated in the TNS_NAMES.ora file.

I would try to ping the Host from the Client and then the try to ping the client from the host. This will establish that the network is functioning. If that is successful, then run tnsping on the client and see if it's successful. If all that works, then is it possible that there are multiple Oracle clients installed on the client PC? Use find to see if there are more than one tnsnames.ora files on the client. If you are still having problems, post the results and someone will surely follow up on them.

HTH,
Patrick

"Mike Harrison" <harrisonm7_at_home.com> wrote in message news:471417c6.0204120704.3f52f4bf_at_posting.google.com...

> The TNS Listener for our Oracle 8.1.6 (NT4 sp6) server seems to have
> stopped working all of a sudden. Nothing happened on the server that
> I'm aware, but now all I get is
>
> ORA-12543: TNS:destination host unreachable
>
> when I try to log into the database with SQLPLUS. The listener's log
> file seems to indicate that the connection was established:
>
> 12-APR-2002 10:55:07 *
> (CONNECT_DATA=(SERVICE_NAME=oracle8.world)(CID=(PROGRAM=c:\orant\bin\SQLPLUS.EXE)(HOST=HOSTNAMEDELETED)(USER=USERNAME)))
> * (ADDRESS=(PROTOCOL=tcp)(HOST=xx.xx.xx.xx)(PORT=1249)) * establish *
> oracle8.world * 0
>
> The entry in the tnsnames.ora:
>
> ORACLE8 =
> (DESCRIPTION =
> (ADDRESS_LIST =
> (ADDRESS = (PROTOCOL = TCP)(HOST = servername)(PORT = 1521))
> )
> (CONNECT_DATA =
> (SERVICE_NAME = oracle8.world)
> )
> )
> What would be the cause of this problem? I can log into the database
> with sqlplus from the server itself, just not from a client. I haven't
> changed the tnsnames.ora or listener.ora file on the server at all. I
> can TNSPING the server and it says "OK". I've tried stopping and
> starting the TNS listener to no avail. Everything was working fine
> with this database yesterday.

-- 
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG