RFC 2979 (rfc2979) - Page 1 of 7

Behavior of and Requirements for Internet Firewalls

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Network Working Group                                           N. Freed
Request for Comments: 2979                                           Sun
Category: Informational                                     October 2000


                    Behavior of and Requirements for
                           Internet Firewalls

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2000).  All Rights Reserved.

Abstract

   This memo defines behavioral characteristics of and interoperability
   requirements for Internet firewalls.  While most of these things may
   seem obvious, current firewall behavior is often either unspecified
   or underspecified and this lack of specificity often causes problems
   in practice.  This requirement is intended to be a necessary first
   step in making the behavior of firewalls more consistent across
   implementations and in line with accepted IP protocol practices.

1. Introduction

   The Internet is being used for an increasing number of mission
   critical applications.  Because of this many sites find isolated
   secure intranets insufficient for their needs, even when those
   intranets are based on and use Internet protocols.  Instead they find
   it necessary to provide direct communications paths between the
   sometimes hostile Internet and systems or networks which either deal
   with valuable data, provide vital services, or both.

   The security concerns that inevitably arise from such setups are
   often dealt with by inserting one or more "firewalls" on the path
   between the Internet and the internal network.  A "firewall" is an
   agent which screens network traffic in some way, blocking traffic it
   believes to be inappropriate, dangerous, or both.

   Note that firewall functions are disjoint from network address
   translation (NAT) functions -- neither implies the other, although
   sometimes both are provided by the same device.  This document only
   discusses firewall functions.



Freed                        Informational
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