I have always beat these problems. But today we took on a new remote client and I could not get in via the tnsnames.ora and listener.ora.

The sitting DBA is a very experienced physical DBA meaning unix and such but not a development DBA.

Neither of us could make it work after 2 hours.

There is nothing left to try and tracing with level 16 was useless.

What else might cause this problem? The above mentioned config files had not been recently modifed - but we also dont know how recently anyone successfully or ever connected to the database.