logfile: provide standards that should be checked
/var/log/messages:
- "journal: Missed 925 kernel messages"
- "Too many "
/var/log/maillog:
- "Recipient address rejected"
- "error"
- "fatal"
- "denied"
/var/log/secure:
- "POSSIBLE BREAK-IN ATTEMPT!"
/var/log/httpd/error_log:
- "PHP Fatal error"
journalctl:
- "identified spam" (Anzahl SPAM-Nachrichten)