# Controlling logging by using the log file

The Network Server uses the `derby.log` file to log problems that it encounters. It also logs connections when the property `derby.drda.logConnections` is set to `true`. The `derby.log` file is created when the Derby server is started. The Network Server then records the time and version. If a log file exists, it is overwritten, unless the property `derby.infolog.append` is set to `true`.

When the Network Server is logging connections, it also logs the Connection Number; this log message is written both to the `derby.log` file and to the Network Server console.

- To turn on connection logging, you can use the servlet interface or you can issue the following command:

      java org.apache.derby.drda.NetworkServerControl
         logconnections on [-h <hostname>] [-p <portnumber>]

- To turn connection logging off you can use the servlet interface or you can issue the following command:

      java org.apache.derby.drda.NetworkServerControl
         logconnections off [-h <hostname>][-p <portnumber>]

See the Derby Developer's Guide for more information about the `derby.log` file.
Parent topic: Derby Network Server advanced topics
Related concepts
Network Server security
Related tasks
Running the Network Server under the security manager
Configuring the Network Server to handle connections
Controlling tracing by using the trace facility