What Are Daemons Daemons are processes that live for a very long time, and augment the operating system in some way. That is, they either: Provide a service to the users, in a persistent fashion, or Provide a service to the operating system itself. Daemons of the first kind include sendmail, the apache web server and telnetd. Daemons of the second kind include kupdated, kflushd and inetd.