After "yum install" I naturally tried "service ntop start" but only to get this:
Starting ntop: service not configured, run ntop manually
Of course, the service was not "configured" - by this ntop means that there is no admin password set for the web interface. To set a password you only need to do this:
ntop --set-admin-password=reallyBadpassword
After this ntop will start just fine. Enjoy!
