Logs are a good way to pin point issues or security breaches. You can configure what is logged by editing the /etc/rsyslog.conf file. The priority of the message will determine which file the logged text is going to be written to. There are 9 priorities that you should be familiar with. The priorities are none, debug, info, notice, warn, err, crit, alert, emerg where debug is the lowest priority and emerg is the highest.