Q: Where can I get a new TNSNAMES.ORA file?

Answer

In previous versions of Oracle, the Oracle client relied on the TNSNAMES.ORA file to resolve the connect identifier. MIT currently uses the Oracle Internet Directory (OID) server. Databases previously listed in TNSNAMES.ORA are now available on the OID server.

For information regarding configuring the Oracle client to use the Oracle Internet Directory server, see:
"TNS could not resolve connect identifier specified", "...could not resolve service name"