OpenSER was designed to log debug and error messages either to “syslog” facility or to standard error display “stderr”. The switching between the two options can be done via command line parameters or configuration file. By default, OpenSER prints log messages to “syslog”.

The messages are printed only if their log level exceeds the threshold set with the “debug” parameter in the configuration file or specified by the command line parameter “-d”.

OpenSER can be configured to report the log messages to a custom syslog facility. You need to to configure your “syslog” daemon and set the “log_facility” OpenSER configuration option to the appropriate value. Later in this document, this feature will be presented in more details.