Network Working Group                                    J. Van Bokkelen
Request for Comments:  1173                           FTP Software, Inc.
                                                             August 1990


             Responsibilities of Host and Network Managers
           A Summary of the "Oral Tradition" of the Internet

Status of this Memo

   This informational RFC describes the conventions to be followed by
   those in charge of networks and hosts in the Internet.  It is a
   summary of the "oral tradition" of the Internet on this subject.
   [RFC Editor's note:  This memo is a contribution by the author of his
   view of these conventions.  It is expected that this RFC will provide
   a basis for the development of official policies in the future.]
   These conventions may be supplemented or amended by the policies of
   specific local and regional components of the Internet.  This RFC
   does not specify a standard, or a policy of the IAB.  Distribution of
   this memo is unlimited.

Table of Contents

   Status of this Memo .............................................. 1
   1. Basic Responsibilities......................................... 1
   2. Responsibilities of Network Managers........................... 2
   3. Responsibilities of Host System Managers....................... 2
   4. Postmaster@foo.bar.baz......................................... 3
   5. Problems and Resolutions....................................... 3
   6. The Illusion of Security....................................... 4
   7. Summary........................................................ 5
   8. Security Considerations........................................ 5
   9. Author's Address............................................... 5

1. Basic Responsibilities

   The Internet is a co-operative endeavor, and its usefulness depends
   on reasonable behaviour from every user, host and router in the
   Internet.  It follows that people in charge of the components of the
   Internet MUST be aware of their responsibilities and attentive to
   local conditions.  Furthermore, they MUST be accessible via both
   Internet mail and telephone, and responsive to problem reports and
   diagnostic initiatives from other participants.

   Even local problems as simple and transient as system crashes or
   power failures may have widespread effects elsewhere in the net.
   Problems which require co-operation between two or more responsible
   individuals to diagnose and correct are relatively common.  Likewise,



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RFC 1173     Responsibilities of Host and Network Managers   August 1990


   the tools, access and experience needed for efficient analysis may
   not all exist at a single site.

   This communal approach to Internet management and maintenance is
   dictated by the present decentralized organizational structure.  The
   structure, in turn, exists because it is inexpensive and responsive
   to diverse local needs.  Furthermore, for the near term, it is our
   only choice; I don't see any prospect of either the government or
   private enterprise building a monolithic, centralized, ubiquitous "Ma
   Datagram" network provider in this century.

2. Responsibilities of Network Managers

   One or more individuals are responsible for every IP net or subnet
   which is connected to the Internet.  Their names, phone numbers and
   postal addresses MUST be supplied to the Internet NIC (or to the
   local or regional transit network's NIC) prior to the network's
   initial connection to the Internet, and updates and corrections MUST
   be provided in a timely manner for as long as the net remains
   connected.

   In order to adequately deal with problems that may arise, a network
   manager must have either:

      A. System management access privileges on every host and router
         connected to the local network, or:

      B. The authority and access to either power off, re-boot,
         physically disconnect or disable forwarding IP datagrams from
         any individual host system that may be misbehaving.

   For all networks, a network manager capable of exercising this level
   of control MUST be accessible via telephone 8 hours a day, 5 days a
   week.  For nets carrying transit traffic, a network manager SHOULD be
   accessible via telephone 24 hours a day.

3. Responsibilities of Host System Managers

   One or more individuals must be responsible for every host connected
   to the Internet.  This person MUST have the authority, access and
   tools necessary to configure, operate and control access to the
   system.  For important timesharing hosts, primary domain name servers
   and mail relays or gateways, responsible individual(s) SHOULD be
   accessible via telephone 24 hours a day, 7 days a week.

   For less-important timesharing hosts or single-user PCs or
   workstations, the responsible individual(s) MUST be prepared for the
   possiblity that their network manager may have to intervene in their



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RFC 1173     Responsibilities of Host and Network Managers   August 1990


   absence, should the resolution of an Internet problem require it.

4. Postmaster@foo.bar.baz

   Every Internet host that handles mail beyond the local network MUST
   maintain a mailbox named "postmaster".  In general, this should not
   simply forward mail elsewhere, but instead be read by a system
   maintainer logged in to the machine.  This mailbox SHOULD be read at
   least 5 days a week, and arrangements MUST be made to handle incoming
   mail in the event of the absence of the normal maintainer.

   A machine's "postmaster" is the normal point of contact for problems
   related to mail delivery.  Because most traffic on the long-haul
   segments of the Internet is in the form of mail messages, a local
   problem can have significant effects elsewhere in the Internet.  Some
   problems may be system-wide, such as disk or file system full, or
   mailer or domain name server hung, crashed or confused.  Others may
   be specific to a particular user or mailing list (incorrect aliasing
   or forwarding, quota exceeded, etc.).

   In either case, the maintainer of a remote machine will normally send
   mail about delivery problems to "postmaster".  Also, "postmaster" is
   normally specified in the "reply-to:" field of automatically
   generated mail error messages (unable to deliver due to nonexistent
   user name, unable to forward, malformed header, etc.).  If this
   mailbox isn't read in a timely manner, significant quantities of mail
   may be lost or returned to its senders.

5. Problems and Resolutions

   Advances in network management tools may eventually make it possible
   for a network maintainer to detect and address most problems before
   they affect users, but for the present, day-to-day users of
   networking services represent the front line.  No responsible
   individual should allow their "dumb-question" filter to become too
   restrictive; reports of the form "I haven't gotten any mumblefrotz
   mail for a week... " or "I could get there this morning, but not
   now..." should always get timely attention.

   There are three basic classes of problems that may have network-wide
   scope:  User-related, host-related and network-related.

      A. User-related problems can range from bouncing mail or
         uncivilized behaviour on mailing lists to more serious
         issues like violation of privacy, break-in attempts or
         vandalism.

      B. Host-related problems may include mis-configured software,



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         obsolete or buggy software and security holes.

      C. Network-related problems are most frequently related to
         routing: incorrect connectivity advertisements, routing
         loops and black holes can all have major impacts.
         Mechanisms are usually in place for handling failure of
         routers or links, but problems short of outright failure
         can also have severe effects.

   Each class of problem has its own characteristics.  User-related
   problems can usually be solved by education, but system managers
   should be aware of applicable federal and state law as well; Privacy
   violations or "cracking" attempts have always been grounds for
   pulling a user's account, but now they can also result in
   prosecution.  Host-related problems are usually resolvable by re-
   configuration or upgrading the software, but sometimes the
   manufacturer needs to be made aware of a bug, or jawboned into doing
   something about it; Bugs that can't be fixed may be serious enough to
   require partial or total denial of service to the offending system.
   Similar levels of escalation exist for network-related problems, with
   the solution of last resort being ostracism of the offending net.

6. The Illusion of Security

   Every host and network manager MUST be aware that the Internet as
   presently constituted is NOT secure.  At the protocol level, much
   more effort has been put into interoperability, reliability and
   convenience than has been devoted to security, although this is
   changing.  Recent events have made software developers and vendors
   more sensitive to security, in both configuration and the underlying
   implementation, but it remains to be demonstrated how much long-term
   effect this will have.  Meanwhile, the existing system survives
   through the co-operation of all responsible individuals.

   Security is subjective; one site might view as idle curiosity what
   another would see as a hostile probe.  Since ultimately the existence
   of the Internet depends on its usefulness to all members of the
   community, it is important for managers to be willing to accept and
   act on other sites' security issues, warning or denying access to
   offending users.  The offended site, in turn, must be reasonable in
   its demands (someone who set off an alarm while idly seeing if the
   sendmail "DEBUG" hole was closed on a "sensitive" host probably
   should be warned, rather than prosecuted).

   Because Internet security issues may require that local management
   people either get in touch with any of their users, or deny an
   offending individual or group access to other sites, it is necessary
   that mechanisms exist to allow this.  Accordingly, Internet sites



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   SHOULD NOT have "general use" accounts, or "open" (without password)
   terminal servers that can access the rest of the Internet.

   In turn, the "sensitive" sites MUST be aware that it is impossible in
   the long term to deny Internet access to crackers, disgruntled former
   employees, unscrupulous competitors or agents of other countries.
   Getting an offender flushed is at best a stop-gap, providing a
   breathing space of a day or an hour while the security holes under
   attack are closed.  It follows that each host's manager is ultimately
   responsible for its security; the more "sensitive" the application or
   data, the more intimate the manager must be with the host's operating
   system and network software and their foibles.

7. Summary

   The heart of the Internet is the unique community of interest
   encompassing its users, operators, maintainers and suppliers.
   Awareness and acceptance of the shared interest in a usable Internet
   is vital to its survival and growth.  The simple conventions
   presented here should be supplemented by common sense as necessary to
   achieve that end.

8. Security Considerations

   Security issues are discussed in Sections 5 and 6.

9. Author's Address

   James B. VanBokkelen
   FTP Software Inc.
   26 Princess St.
   Wakefield, MA  01880

   Phone:  617-246-0900

   EMail: jbvb@ftp.com















Van Bokkelen                                                    [Page 5]