I have an alias which inexplicably stopped working last Friday, when I attempt to test the alias I get an ORA-03113 error. I can successfully connect to any of the other aliases in my tnsnames file, and other machines can connect to the remote database specified in the service name (the same one I get the error when trying to connect). I can tnsping the alias and get a response, but cannot connect from this particular machine to the remote database. All workstations are on the same hub, so no network connectivity issues here. Also I tried replacing the tnsnames file on this machine with one from a machine which could connect and still got the error. What gives?