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- 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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- Van Bokkelen [Page 1]
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- RFC 1173 Responsibilities of Host and Network Managers August 1990
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- 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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- Van Bokkelen [Page 2]
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- RFC 1173 Responsibilities of Host and Network Managers August 1990
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- 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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- Van Bokkelen [Page 3]
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- RFC 1173 Responsibilities of Host and Network Managers August 1990
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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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- Van Bokkelen [Page 4]
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- RFC 1173 Responsibilities of Host and Network Managers August 1990
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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
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- Van Bokkelen [Page 5]
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