Internet: It is public network. This consist of thousand individual networks and millions of computers located around the world. The internet is not owned or administered by any central managing body. This feature become vital to the productivity of most business.
Internet have many different types of services available such as e-mail, the web and Usenet newsgroups. An internet connection for a network consist of a telephone connection to an ISP (Internet Service Protocol). Internet require more security, so for this purpose firewall system is implemented.
Intranet: It is a private network or it is company´s own network. Company use this feature for internal use. For example, company establish it´s own web server, for placing documents such as employee handbooks purchasing from or other information that company publishes for internal use. It also has internet services such as FTP servers or Usenet servers.