First, thanks for the replies so far. Here's what I've found: Yes, it is a Windows 2000 client with multiple Oracle Homes. I have searched the entire registry and there are no references to TNS_ADMIN. tnsping doesn't give any additional information. Below is the entire output from tnsping: C:\Documents and Settings\JonK>tnsping clsdev.world TNS Ping Utility for 32-bit Windows: Version 8.1.7.0.0 - Production on 18-JAN-2006 09:45:21 (c) Copyright 1997 Oracle Corporation. All rights reserved. Attempting to contact (ADDRESS=(PROTOCOL=TCP)(HOST=ud505)(PORT=1521)) OK (110 msec) C:\Documents and Settings\JonK> Below is a connection trace as reported by SQL*Navigator. It shows that the tnsnames.ora from the correct oracle home is being used. oci.dll found 2) Oracle Home Key is SOFTWARE\ORACLE\HOME1 Looking for TNS_ADMIN environmental variable TNS_ADMIN environmental variable doesnt exist, looking for TNS_ADMIN reg key using home key: >SOFTWARE\ORACLE\HOME1< Oracle Path is now C:\ora817NT\network\ADMIN Looking for C:\ora817NT\network\ADMIN\tnsnames.ora tnsnames.ora found ... I don't have access to the particular box in question (Data Security has it locked down - it's a development box, go figure!), so I can't verify the tns entry on the server. However, this tns entry allows other developers to connect to the instance without a problem. I will continue to try to verify the tnsnames.ora entry on the server. Until then, is there anything else I can check? Thanks, Jon --- Alex Gorbachev <gorbyx@xxxxxxxxx> wrote: > Just to add 2 cents to Mladen's comment. > On server side use "lsnrctl status" or "lsnrctl > services" to see the > services that are registered with a listener. I > assume your > environment is set correctly and listener name is by > default. > > Alex > PS: Welcome back Malden. Heh, you missed few posts > to comment. :) > > 2006/1/18, Mladen Gogala <gogala@xxxxxxxxxxxxx>: > > > > On 01/18/2006 10:50:53 AM, Jonathan Knight wrote: > > > I have a strange (to me anyway) problem with > TNS. > > > > The problem is not strange. It is a configuration > problem. > __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com -- //www.freelists.org/webpage/oracle-l