We have many client machines (oracle developer 6i installed which has Oracle 8i client) suddenly stopping connections to the database (Oracle 9i). tnsnames.ora is fine, because it used to connect before. I can ping to the database host, but when doing tnsping80 to the tns entry it is giving TNS-12560 protocol adapter error or TNS 12571 packet writer failure. I tried to re-install Oracle, but no use. Finally we have to re-intsall win2K/Win XP and install Oracle Dev 6i again to solve the problem.
Please give advice.