# 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`.

See derby.drda.logConnections property for information on this property.

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`.See "derby.infolog.append" in the Derby Reference Manual for information on this property.

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, use the following command (all on one line):

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

- To turn off connection logging, use the following command (all on one line):

      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 tasks
Configuring the Network Server to handle connections
Controlling tracing by using the trace facility