Cause: The server shut down because connection establishment or communication with a client failed to complete within the allotted time interval. This may be a result of network or system delays; or this may indicate that a malicious client is trying to cause a Denial of Service attack on the server.
Action: If the error occurred because of a slow network or system, reconfigure one or all of the parameters SQLNET.INBOUND_CONNECT_TIMEOUT, SQLNET.SEND_TIMEOUT, SQLNET.RECV_TIMEOUT in sqlnet.ora to larger values. If a malicious client is suspected, use the address in sqlnet.log to identify the source and restrict access. Note that logged addresses may not be reliable as they can be forged (e.g. in TCP/IP).