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Network Working Group                                         D. CrockerRequest for Comments: 1775                        Brandenburg ConsultingCategory: Informational                                       March 1995To Be "On" the InternetStatus of this Memo   This memo provides information for the Internet community.  This memo   does not specify an Internet standard of any kind.  Distribution of   this memo is unlimited.Abstract   The Internet permits different levels of access for consumers and   providers of service.  The nature of those differences is quite   important in the capabilities They afford.  Hence, it is appropriate   to provide terminology that distinguishes among the range, so that   the Internet community can gain some clarity when distinguishing   whether a user (or an organization) is "on" the Internet.  This   document suggests four terms, for distinguishing the major classes of   access.1.   INTRODUCTION   The Internet is many things to many people.  It began as a technology   and has grown into a global service.  With the growth has come   increased complexity in details of the technology and service,   resulting in confusion when trying to determine whether a given user   is "on" the Internet.  Who is on the Internet?  What capabilities do   they have?  This note is an attempt to aid Internet consumers and   providers in determining the basic types of end-user access that   distinguish critical differences in Internet attachment.   The list was developed primarily for the perspective of users, rather   than for the technical community. The definitions in this list take   the perspective that users are primarily interested in application   services.   A curious implication is that some of the definitions do   not rely on the direct use of the underlying Internet connectivity   protocols, TCP/IP.  For many technical discussions, therefore, these   terms will not be appropriate.Crocker                                                         [Page 1]

RFC 1775                To Be "On" the Internet               March 19952.   LABELS FOR INTERNET ACCESS   The following definitions move from "most" to "least" Internet   access, from the perspective of the user (consumer). The first term   is primarily applicable to Internet service providers.  The remaining   terms are primarily applicable to consumers of Internet service.   FULL ACCESS      This is a permanent (full-time) Internet attachment running      TCP/IP, primarily appropriate for allowing the Internet community      to access application servers, operated by Internet service      providers.  Machines with Full access are directly visible to      others attached to the Internet, such as through the Internet      Protocol's ICMP Echo (ping) facility.  The core of the Internet      comprises those machines with Full access.   CLIENT ACCESS      The user runs applications that employ Internet application      protocols directly on their own computer platform, but might not      be running underlying Internet protocols  (TCP/IP), might not have      full-time access, such as through dial-up, or might have      constrained access, such as through a firewall.  When active,      Client users might be visible to the general Internet, but such      visibility cannot be predicted.  For example, this means that most      Client access users will not be detected during an empirical      probing of systems "on" the Internet at any given moment, such as      through the ICMP Echo facility.   MEDIATED ACCESS      The user runs no Internet applications on their own platform.  An      Internet service provider runs applications that use Internet      protocols on the provider's platform, for the user.  User has      simplified access to the provider, such as dial-up terminal      connectivity.  For Mediated access, the user is on the Internet,      but their computer platform is not.  Instead, it is the computer      of the mediating service (provider) which is on the Internet.   MESSAGING ACCESS      The user has no Internet access, except through electronic mail      and through netnews, such as Usenet or a bulletin board service.      Since messaging services can be used as a high-latency -- i.e.,      slow -- transport service, the use of this level of access for      mail-enabled services can be quite powerful, though not      interactive.Crocker                                                         [Page 2]

RFC 1775                To Be "On" the Internet               March 19953.   SAMPLE USAGE   The test of a nomenclature is, of course, its application to real-   life situations.  Two simple cases involve home users.  If a user   accesses the Internet by running a terminal program on their PC and   then dials up a public service which provides the Internet   applications, then that user has Mediated Internet access.  The   public service has Client or Full access, but the user does not.  On   the other hand, users who access via SLIP or PPP are running Internet   applications on their own PCs and they have Client Internet access.   Many corporations now have a full-time link to the Internet.  The   link is based on TCP/IP and usually has a number of Internet servers   running, for email exchange and for making public corporate data   available to the rest of the world, such as through the World Wide   Web and Gopher.  Clearly, the corporation is "on" the Internet, with   Full Internet access.   What about a user in that corporation?  Many corporations today   separate their internal internet from the public Internet via a   firewall.  If a user from the internal internet has a desktop   computer and reaches out to the Internet, through the firewall, by   running any Internet applications, such as a Web browser, then that   user has Client Internet access.   Some corporations will not allow this, instead requiring all software   which touches the public Internet to be run on specially-administered   machines which are part of the corporation's firewall suite of   services.  Hence, users must make a terminal connection to the   special machines, from there running the Internet applications.  Such   users have Mediated Internet access, the same as home users who dial   up a public service.4.   SECURITY CONSIDERATIONS   This specification does NOT, itself, provide or define any security-   related mechanisms.  However it does describe scenarios with   different security implications for users and providers.  Readers of   this discussion are cautioned to consider those implications when   choosing a service.5.   ACKNOWLEDGMENTS   Development of these definitions was spurred by many public and   private discussions in which confusion over Internet access reigned.   Convergence on an initial set of three terms was the result of   discussion on the Big-Internet mailing list, particularly from   comments made by Alan Barret, Howard Berkowitz, Noel Chiappa, SteveCrocker                                                         [Page 3]

RFC 1775                To Be "On" the Internet               March 1995   Goldstein, Iain Hanson, Gary Malkin, Bob McKisson, Tim O'Reilly, Dave   Piscitello and Bill Simpson.  Eventually, the need for a fourth   category became evident and was discussed further with the   participants on the list.  This does not mean that any of them   necessarily endorses the terms and definitions provided, merely that   their notes assisted my thinking on the topic.  After the initial   round of public discussion, Smoot Carl-Mitchell and John Quarterman   of Texas Internet Consulting developed terminology for similar   categories and served to prompt modification of this set, described,   here, to distinguish between provider and consumer forms of access   and emphasize the role of Full access in defining the Internet core.6.   Security Considerations   Security issues are not discussed in this memo.7.   Author's Address   David H. Crocker   Brandenburg Consulting   675 Spruce Dr.   Sunnyvale, CA 94086 USA   Phone:    +1 408 246 8253   Fax:      +1 408 249 6205   EMail:    dcrocker@mordor.stanford.eduCrocker                                                         [Page 4]