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Network Working Group                                    J. Van BokkelenRequest for Comments:  1173                           FTP Software, Inc.                                                             August 1990Responsibilities of Host and Network ManagersA Summary of the "Oral Tradition" of the InternetStatus 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 ..............................................11. Basic Responsibilities.........................................12. Responsibilities of Network Managers...........................23. Responsibilities of Host System Managers.......................24. Postmaster@foo.bar.baz.........................................35. Problems and Resolutions.......................................36. The Illusion of Security.......................................47. Summary........................................................58. Security Considerations........................................59. Author's Address...............................................51. 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,Van Bokkelen                                                    [Page 1]

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 theirVan Bokkelen                                                    [Page 2]

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,Van Bokkelen                                                    [Page 3]

RFC 1173     Responsibilities of Host and Network Managers   August 1990         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 sitesVan Bokkelen                                                    [Page 4]

RFC 1173     Responsibilities of Host and Network Managers   August 1990   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 Sections5 and6.9. Author's Address   James B. VanBokkelen   FTP Software Inc.   26 Princess St.   Wakefield, MA  01880   Phone:  617-246-0900   EMail: jbvb@ftp.comVan Bokkelen                                                    [Page 5]