One could have an Oracle installation (10g, in my case) on a Windows XP machine). To bypass the problem of connection loss you could set SQLNET.AUTHENTICATION_SERVICES to none but then sqlplus / as sysdba won’t work anymore (obviously).

So I set my SQLNET.AUTHENTICATION_SERVICES back to NTS (using TNSNAMES)

The problem of connection loss doesn’t seem to appear anymore, maybe it’s because of a correct network binding (listener)?

C:\oracle\product\10.2.0\db_1\NETWORK\ADMIN>type sqlnet.ora

SQLNET.AUTHENTICATION_SERVICES= (NTS)

NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)