The configuration file, specified by the `-c CONFIGFILE` [command line option](00001004051000), allows you to specify some startup options.
These cannot be stored in a [configuration zettel](00001004020000) because they are needed before Zettelstore can start or because of security reasons.
For example, Zettelstore needs to know in advance on which network address it must listen or where zettel are stored.
An attacker that is able to change the owner can do anything.
Therefore, only the owner of the computer on which Zettelstore runs can change this information.

The file for startup configuration must be created via a text editor in advance.

The syntax of the configuration file is the same as for any zettel metadata.
The following keys are supported: