I am not a DBA so my knowledge is limited however one of my users is experiencing an ORA-12571 error on her machine. If I attempt to log on at that client I get the same error, however I can log on from other clients. I checked the tnsnames.ora and the entry is identical to everyone else's. I did a tnsping of the offending database and I receive the 12571 error. If I just ping the server ip address I get replies. I attempted to ping our test server and get the same result. I can ping the server but receive the 12571 error on the tnsping. When I attempted to log on to the db under my userid via sqlplus I receive the error ORA-12560 Protocol Adapter Error. Does anyone have an idea what the problem might be? Thanks in advance, replies to the forum or to firstname.lastname@example.org would be greatly appreciated!