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Versions: 00 01 02 03 04 rfc2725                                        
Internet Engineering Task Force                             Curtis Villamizar
INTERNET-DRAFT                                                          UUNET
draft-ietf-rps-auth-03                                    Cengiz Alaettinoglu
                                                                          ISI
                                                               David M. Meyer
                                                                        Cisco
                                                                 Sandy Murphy
                                                                          TIS
                                                               April 22, 1999



                         Routing Policy System Security



Status of this Memo



   This document is an Internet-Draft and is in full conformance with all
   provisions of Section 10 of RFC2026.


   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that other
   groups may also distribute working documents as Internet-Drafts.


   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet- Drafts as reference mate-
   rial or to cite them other than as ``work in progress.''


   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt


   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.


   Copyright (C) The Internet Society (April 22, 1999).  All Rights Re-
   served.



Abstract



   The RIPE database specifications and RPSL language define languages
   used as the basis for representing information in a routing policy
   system.  A repository for routing policy system information is known
   as a routing registry.  A routing registry provides a means of ex-

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   changing information needed to address many issues on importance to
   the operation of the Internet.  The implementation and deployment of
   a routing policy system must maintain some degree of integrity to be
   of any operational use.  This document addresses the need to assure
   integrity of the data by providing an authentication and authorization
   model.



1   Overview



   The Internet Routing Registry (IRR) has evolved to meet a need for
   Internet-wide coordination.  This need was described in RFC-1787, an
   informational RFC prepared on behalf of the IAB [16].  The following
   summary appears in Section 7 of RFC-1787.



      While ensuring Internet-wide coordination may be more and more
      difficult, as the Internet continues to grow, stability and con-
      sistency of the Internet-wide routing could significantly benefit
      if the information about routing requirements of various organi-
      zations could be shared across organizational boundaries.  Such
      information could be used in a wide variety of situations ranging
      from troubleshooting to detecting and eliminating conflicting
      routing requirements.  The scale of the Internet implies that the
      information should be distributed.  Work is currently underway to
      establish depositories of this information (Routing Registries),
      as well as to develop tools that analyze, as well as utilize this
      information.



   A routing registry must maintain some degree of integrity to be of
   any use.  The degree of integrity required depends on the usage of the
   routing policy system.


   An initial intended usage of routing policy systems such as the RIPE
   database had been in an advisory capacity, documenting the intended
   routing policies for the purpose of debugging.  In this role a very
   weak form of authentication was deemed sufficient.


   The IRR is increasingly used for purposes that have a stronger re-
   quirement for data integrity and security.  This document addresses
   issues of data integrity and security that is consistent with the
   usage of the IRR and which avoids compromising data integrity and se-
   curity even if the IRR is distributed among less trusted repositories.



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2   Background



   An early routing policy system used in the NSFNET, the policy routing
   database (PRDB), provided a means of determining who was authorized
   to announce specific prefixes to the NSFNET backbone.  The need for
   a policy database was recognized as far back as 1989 [6, 4].  By 1991
   the database was in place [5].  Authentication was accomplished by
   requiring confirmation and was a manually intensive process.  This
   solved the problem for the NSFNET, but was oriented toward holding the
   routing policy of a single organization.


   The problem since has become more difficult.  New requirements have
   emerged.



  1.  There is a need to represent the routing policies of many organiza-
      tions.

  2.  CIDR and overlapping prefixes and the increasing complexity of
      routing policies and the needs of aggregation have introduced new
      requirements.

  3.  There is a need to assure integrity of the data and delegate au-
      thority for the data representing specifically allocated resources
      to multiple persons or organizations.

  4.  There is a need to assure integrity of the data and distribute the
      storage of data subsets to multiple repositories.



   The RIPE effort specificly focused on the first issue and needs of the
   European community.  Its predecessor, the PRDB, addressed the needs of
   a single organization, the NSF. The RIPE database formats as described
   in [2] were the basis of the original IRR.


   Routing protocols themselves provide no assurance that the origination
   of a route is legitimate and can actually reach the stated destina-
   tion.  The nature of CIDR allows more specific prefixes to override
   less specific prefixes [9, 17 , 8].  Even with signed route origina-
   tion, there is no way to determine if a more specific prefix is legit-
   imate and should override a less specific route announcement without a
   means of determining who is authorized to announce specific prefixes.
   Failing to do so places no assurance of integrity of global routing
   information and leaves an opportunity for a very effective form of
   denial of service attack.


   The Routing Policy System Language (RPSL) [1, 13 ] was a fairly sub-
   stantial evolutionary step in the data representation which was
   largely targeted at addressing the second group of needs.  The PRDB
   accommodated CIDR in 1993 [12] and the RIPE database accommodated the



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   entry of CIDR prefixes from inception, but RPSL provides many needed
   improvements including explicit support for aggregation.


   This document addresses the third group of needs identified above.


   While the current implementation supporting weak authentication
   doesn't guarantee integrity of the data, it does provide extensive
   mechanisms to make sure that all involved parties get notified when
   a change is made to the database, whether the change was malicious
   or intended.  This provides inadequate protection against additions.
   Since the software is increasingly used to configure the major parts
   of the Internet infrastructure, it is not considered to be adequate
   anymore to know about and have the ability roll back unintended
   changes.  Therefore, more active security mechanism need to be de-
   veloped to prevent such problems before they happen.


   A separate document will be needed to address the fourth group of
   needs.



3   Implicit Policy Assumptions



   The authorization model encodes certain policies for allocation of
   address numbers, AS numbers, and for the announcement of routes.  Im-
   plicit to the authorization model are a very limited number of policy
   assumptions.



  1.  Address numbers are allocated hierarchically.  The IANA delegates
      portions of the address space to the regional registries (currently
      ARIN, APNIC and RIPE), which in turn delegate address space to
      their members, who can assign addresses to their customers.

  2.  AS numbers are allocated either singly or in small blocks by reg-
      istries.  Registries are allocated blocks of AS numbers, thereby
      making the allocation hierarchical.

  3.  Routes should only be announced with the consent of the holder of
      the origin AS number of the announcement and with the consent of
      the holder of the address space.

  4.  AS numbers and IP address registries may be different entities from
      routing registries.



   For subsets of any of these three allocation spaces, network ad-
   dresses, AS numbers, and routes, these restrictions may be loosened
   or disabled by specifying a very weak authorization method or an
   authentication method of ``none''.  However, even when no authenti-
   cation mechanism is used, all involved parties can be notified about



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   the changes that occurred through use of the existing ``notify'' at-
   tribute.



4   Scope of Security Coverage



   This document is intended only to provide an authentication and au-
   thorization model to insure the integrety of the policy data in a reg-
   istry.  Only authetication and authorization of additions, deletions,
   and changes to the database are within the scope of this document.
   Authentication and authorization of database queries is explicitly
   out of scope.  Mutual authentication of queries, that is authenticat-
   ing both the origin of the query and the repository from which query
   results are obtained, is also out of scope.



5   Organization of this Document



   Familiarity with RIPE-181 [2] and RPSL [1] is assumed throughout this
   document.  Goals are described in Section 6.  Section 7 through Sec-
   tion 9 provide descriptions of the changes and discussion.  Section 10
   provides a concise summary of data formats and semantics.  Appendix B
   through Appendix D provide additional technical discussion, examples,
   and deployment considerations.



      Goals and Requirements    Section 6 provides a more detailed descrip-
      tion of the issues and identifies specific problems that need to
      be solved, some of which require a degree of cooperation in the
      Internet community.


      Data Representation    Section 7 provides some characteristics of RPSL
      and formats for external representations of information.


      Authentication Model    Section 8 describes current practice, proposes
      additional authentication methods, and describes the extension
      mechanism if additional methods are needed in the future.


      Authorization Model    Section 9 describes the means of determining
      whether a transaction contains the authorization needed to add,
      modify, or delete specific data objects, based on stated authenti-
      cation requirements in related data objects.


      Data Format Summaries    Section 10 provides a concise reference to
      the data formats and steps in transaction processing.


      Technical Discussion    Section B contains some discussion of techni-
      cal tradeoffs.



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      Common Operational Cases    Section C provides some examples drawn
      from past operational experience with the IRR.


      Deployment Considerations    Section D describes some deployment is-
      sues and discusses possible means of resolution.



6   Goals and Requirements



   The Internet is an open network.  This openness and the large scale of
   the Internet can present operational problems.  Technical weaknesses
   that allow misconfiguration or errant operation in part of the network
   to propagate globally or which provide potentials for simple denial
   of service attacks should be eliminated to the extent that it is prac-
   tical.  The integrity of routing information is critical in assuring
   that traffic goes where it is supposed to.


   An accidental misconfiguration can direct traffic toward routers that
   cannot reach a destination for which they are advertising reachabil-
   ity.  This is commonly caused by misconfigured static routes though
   there are numerous other potential causes.  Static routes are often
   used to provide constant apparent reachability to single homed desti-
   nations.  Some of the largest ISPs literally have thousands of static
   routes in their networks.  These are often entered manually by op-
   erators.  Mistyping can divert traffic from a completely unrelated
   destination to a router with no actual reachability to the advertised
   destination.  This can happen and does happen somewhat regularly.  In
   addition, implementation bugs or severe misconfigurations that result
   in the loss of BGP AS path information or alteration of prefix length
   can result in the advertisement of large sets of routes.  Though con-
   siderably more rare, on a few occasions where this has occurred the
   results were catastrophic.


   Where there is the potential for an accidental misconfiguration in
   a remote part of the Internet affecting the global Internet there is
   also the potential for malice.  For example, it has been demonstrated
   by accident that multiple hour outages at a major institution can be
   caused by a laptop and a dial account if proper precautions are not
   taken.  The dial account need not be with the same provider used by
   the major institution.


   The potential for error is increased by the CIDR preference for more
   specific routes [8].  If an institution advertises a single route of
   a given length and a distant router advertises a more specific router
   covering critical hosts, the more specific route, if accepted at all,
   is preferred regardless of administrative weighting or any routing
   protocol attributes.


   There is a need to provide some form of checks on whether a route ad-
   vertisement is valid.  Today checks are typically made against the



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   border AS advertising the route.  This prevents accepting routes from
   the set of border AS that could not legitimately advertise the route.
   Theses checks rely on the use of information registered in the IRR
   to generate lists of prefixes that could be advertised by a specific
   border AS. Checks can also be made against the origin AS. If policy
   information were sufficiently populated, checks could be made against
   the entire AS path, but this is not yet feasible.


   The use of a routing registry can also make it more difficult for pre-
   fixes to be used without authorization such as unallocated prefixes or
   prefixes allocated to another party.


   In summary, some of the problems being addressed are:



   o  Localizing the impact of accidental misconfiguration made by Inter-
      net Providers to that provider's networks only.

   o  Eliminating the potential for an Internet provider's customer to
      use malicious misconfiguration of routing as a denial of service
      attack if the provider router filters their customers.  Localizing
      the denial of service to that Internet provider only if the immedi-
      ate Internet service provider does not route filter their customers
      but other providers route filter the route exchange at the inter-
      provider peering.

   o  Eliminating the unauthorized use of address space.



   If the data within a routing registry is critical, then the ability
   to change the data must be controlled.  Centralized authorities can
   provide control but centralization can lead to scaling problems (and
   is politically distasteful).


   Address allocation and name allocation is already delegated.  Since
   delegation can be to outside registries it is at least somewhat dis-
   tributed [11].  Autonomous System (AS) numbers are allocated by the
   same authorities.  It makes sense to delegate the routing number space
   in a manner similar to the address allocation and AS number alloca-
   tion.  The need for this delegation of authority to numerous reg-
   istries increases the difficulty of maintaining the integrity of the
   body of information as a whole.


   As a first step, the database can be somewhat centrally administered
   with authority granted to many parties to change the information.
   This is the case with the current IRR. There are a very small number
   of well trusted repositories and a very large number of parties au-
   thorized to make changes.  Control must be exercised over who can make
   changes and what changes they can make.  The distinction of who vs
   what separates authentication from authorization.



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   o  Authentication is the means to determine who is attempting to make
      a change.


   o  Authorization is the determination of whether a transaction pass-
      ing a specific authentication check is allowed to perform a given
      operation.



   Different portions of the database will require different methods of
   authentication.  Some applications will require authentication based
   on strong encryption.  In other cases software supporting strong en-
   cryption may not be necessary or may not be legally available.  For
   this reason multiple authentication methods must be supported, se-
   lected on a per object basis through the specification of authen-
   tication methods in the maintainer object ``auth'' attribute.  The
   authentication methods may range from very weak data integrity checks
   to cryptographicly strong signatures.  The authorization model must
   insure that the use of weak integrity checks in parts of the database
   does not compromise the overall integrity of the database.


   Additional requirements are placed on the authorization model if the
   database is widely distributed with delegations made to parties that
   may not be trustworthy or whose security practices may be lacking.
   This problem must be addressed in the authorization model in order to
   enable later evolution to a more distributed routing registry.


   Autonomous system numbers can be delegated in blocks and subdelegated
   as needed and then individual AS numbers assigned.  Address alloca-
   tion is a simple numeric hierarchy.  Route allocation is somewhat
   more complicated.  The key attributes in a route object (key with re-
   gard to making it unique) contains both an address prefix and an AS
   number, known as the origin AS. The addition of a route object must
   be validated against both the authorization criteria for the AS and
   the address prefix.  Route objects may exist for the same prefix with
   multiple origin AS values due to a common multihoming practice that
   does not require a unique origin AS. There is often no correlation be-
   tween the origin AS of a prefix and the origin AS of overlapping more
   specific prefixes.


   There are numerous operational cases that must be accommodated.  Some
   of the more common are listed below.  These are explored in greater
   detail in Appendix C with discussion of technical tradeoffs in Ap-
   pendix B.



   o  simple hierarchical address allocation and route allocation

   o  aggregation and multihomed more specific routes

   o  provider independent addresses and multiple origin AS



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   o  changing Internet service providers

   o  renumbering grace periods



   The authorization model must accommodate a variety of policies regard-
   ing the allocation of address space and cannot mandate the use of any
   one model.  There is no standardization of address allocation policies
   though guidelines do exist [11, 18 ].  Whether authorization allows the
   recovery of address space must be selectable on a per object basis and
   may differ in parts of the database.  This issue is discussed further
   in Appendix B.



7   Data Representation



   RPSL provides a complete description of the contents of a routing
   repository [1].  Many RPSL data objects remain unchanged from the RIPE
   and RPSL references the RIPE-181 specification as recorded in RFC-1786
   [2].  RPSL provides external data representation.  Data may be stored
   differently internal to a routing registry.


   Some database object types or database attributes must be added to
   RPSL to record the delegation of authority and to improve the authen-
   tication and authorization mechanisms.  These additions are very few
   and are described in Section 8 and Section 9.


   Some form of encapsulation must be used to exchange data.  The de-
   facto encapsulation has been the one which the RIPE tools accept, a
   plain text file or plain text in the body of an RFC-822 formatted mail
   message with information needed for authentication derived from the
   mail headers or the body of the message.  Merit has slightly modified
   this using the PGP signed portion of a plain text file or PGP signed
   portion of the body of a mail message.  These very simple forms of
   encapsulation are suitable for the initial submission of a database
   transaction.


   The encapsulation of registry transaction submissions, registry
   queries and registry responses and exchanges between registries is
   outside the scope of this document.  The encapsulation of registry
   transaction submissions and exchanges between registries is outside
   the scope of this document.



8   Authentication Model



   The maintainer objects serve as a container to hold authentication
   filters.  A reference to a maintainer within another object defines



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   authorization to perform operations on the object or on a set of re-
   lated objects.  The maintainer is typically referenced by name in mnt-
   by attributes of objects.  Further details on the use of maintainers
   are provided in Section 9.1.


   The maintainer contains one or more ``auth'' attributes.  Each
   ``auth'' attribute begins with a keyword identifying the authenti-
   cation method followed by the authentication information needed to
   enforce that method.  The PGPKEY method is slightly syntactically
   different in that the method PGPKEY is a substring.


   Authentication methods currently supported include the following.
   Note that pgp-from is being replaced by the pgpkey (see Section 10 and
   [21]).



   mail-from   This is a very weak authentication check and is discour-
      aged.  The authentication information is a regular expression over
      ASCII characters.  The maintainer is authenticated if the from or
      reply-to fields in RFC-822 mail headers are matched by this regular
      expression.  Since mail forgery is quite easy, this is a very weak
      form of authentication.

   crypt-pw   This is another weak form of authentication.  The authenti-
      cation information is a fixed encrypted password in UNIX crypt for-
      mat.  The maintainer is authenticated if the transaction contains
      the clear text password of the maintainer.  Since the password
      is in clear text in transactions, it can be captured by snooping.
      Since the encrypted form of the password is exposed, it is subject
      to password guessing attacks.

   pgp-from   This format is being replaced by the ``pgpkey'' so that the
      public key certificate will be available to remote repositories.
      This is Merit's PGP extension.  The authentication information
      is a signature identity pointing to an external public key ring.
      The maintainer is authenticated if the transaction (currently PGP
      signed portion of a mail message) is signed by the corresponding
      private key.

   pgpkey  This keyword takes the form ``PGPKEY-hhhhhhhh'', where ``hh-
      hhhhhh'' is the hex representation of the four bytes id of the PGP
      public key used for authentication.  The public key certificate is
      stored in a separate object as described in [21].



   Repositories may elect to disallow the addition of ``auth'' attributes
   specifying weaker forms of authentication and/or disallow their use
   in local transaction submissions.  Repositories are encouraged to dis-
   allow the addition of ``auth'' attributes with the deprecated ``pgp-
   from'' method.



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   Any digital signature technique can be used for authentication.
   Transactions should be signed using multiple digital signature tech-
   niques to allow repositories or mirrors that only use a subset of the
   techniques to verify at least one of the signatures.  Any digital sig-
   nature techniques would be applicable.  One that may be supported in
   the in the future is DSA [14, 15 ].  Numerous digital signature algo-
   rithms are described in [20].



9   Authorization Model



   The authorization model must accommodate the requirements outlined
   in Section 6.  A key feature of the authorization model is the recog-
   nition that authorization for the addition of certain types of data
   objects must be derived from related data objects.


   With multiple repositories, objects not found in RPSL are needed to
   control AS delegations and new attributes are needed in existing ob-
   jects to control subdelegation.  Objects are also needed to provide
   query information for other repositories.



9.1   Maintainer Objects



   The maintainer objects serve as a container to hold authentication
   filters.  The authentication methods are described in Section 8.  The
   maintainer can be referenced by name in other objects, most notably in
   the mnt-by attributes of those objects.


   Maintainers themselves contain mnt-by attributes.  In some cases the
   mnt-by in a maintainer will reference the maintainer itself.  In this
   case, authorization to modify the maintainer is provided to a (usu-
   ally very limited) set of identities.  A good practice is to create
   a maintainer containing a long list of identities authorized to make
   specific types of changes but have the maintainer's mnt-by attribute
   reference a far more restrictive maintainer more tightly controlling
   changes to the maintainer object itself.


   The mnt-by attribute is mandatory in all objects.  Some data already
   exists without mnt-by attributes.  A missing mnt-by attribute is in-
   terpreted as the absence of any control over changes.  This is highly
   inadvisable and most repositories will no longer allow this.


   An additional maintainer reference can occur through a new attribute,
   ``mnt-routes'', and is used in aut-num, inetnum and route objects.
   The ``mnt-routes'' attribute is an extension to RPSL and is described
   in detail in Section 10.



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   A mnt-routes attribute in an aut-num object allows addition of route
   objects with that AS number as the origin to the maintainers listed.
   A mnt-routes attribute in an inetnum object allows addition of route
   objects with exact matching or more specific prefixes.  A mnt-routes
   attribute in a route object allows addition of route objects with ex-
   act matching or more specific prefixes.  A mnt-routes attribute does
   not allow changes to the aut-num, inetnum, or route object where they
   appear.  A mnt-routes may optionally be constrained to only apply to a
   subset of more specific routes.


   Where ``mnt-routes'' or ``mnt-lower'' are applicable, any maintainer
   referenced in the ``mnt-by'' still apply.  The set of applicable main-
   tainers for whatever check is being made is the union of the ``mnt-
   routes'' or ``mnt-lower'' and the ``mnt-by''.  For example, when au-
   thorizing a route object software would look at ``mnt-routes'', if it
   does not exist, look at ``mnt-lower'', if that does not exist look at
   ``mnt-by''.



9.2   as-block and aut-num objects



   An ``as-block'' object is needed to delegate a range of AS numbers to
   a given repository.  This is needed for authorization and it is needed
   to avoid having to make an exhaustive search of all repositories to
   find a specific AS. This search would not be an issue now but would
   be if a more distributed routing repository is used.  Distributed
   registry issues are not within the scope of this document.


   The ``as-block'' object also makes it possible to separate AS number
   allocation from registration of AS routing policy.



     as-block:         AS1321 - AS1335
     ...



   The ``aut-num'' describes the routing policy for an AS and is criti-
   cal for router configuration of that AS and for analysis performed by
   another AS. For the purpose of this document it is sufficient to con-
   sider the aut-num solely as a place holder identifying the existence
   of an AS and providing a means to associate authorization with that AS
   when adding ``route'' objects.


   The ``as-block'' object is proposed here solely as a means of record-
   ing the delegation of blocks of AS numbers to alternate registries and
   in doing so providing a means to direct queries and a means to support
   hierarchical authorization across multiple repositories.



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9.3   inetnum objects



   A delegation attribute is needed in the inetnum and route object.
   This will accommodate the delegation of address space from IANA to
   regional IP registries.  When the routing registry becomes more widely
   distributed a delegation attribute is needed to support any subdelega-
   tions to more localized registries or delegations to Internet provider
   operated registries or organizations who may prefer to run their own
   routing registry.  The delegation attribute for an inetnum or a route
   object can be multi-valued and refers to all registries in which more
   specific route objects can be found.



     inetnum:         193.0.0.0 - 193.0.0.255
     ...
     source:          IANA



   The ``inetnum'' exists to support address allocation.  For external
   number registries, such as those using ``[r]whoisd[++]'' the ``inet-
   num'' can serve as a secondary record that is added when an address
   allocation is made in the authoritative database.  Such records could
   be added by a address registry such as ARIN as a courtesy to the cor-
   responding routing registry.



9.4   route objects



   Currently there are a quite few route objects in more than one reg-
   istry.  Quite a few are registered with origin AS for which they have
   never been announced.  There is a legitimate reason to be in more than
   one origin AS.


   The ``route'' object is used to record routes which may appear in the
   global routing table.  Explicit support for aggregation is provided.
   Route objects exist both for the configuration of routing information
   filters used to isolate incidents of erroneous route announcements
   (Section 6) and to support network problem diagnosis.



9.5   reclaim and no-reclaim attributes



   A reclaim attribute is needed in as-block, inetnum and route objects.
   The reclaim attribute allows a control to be retained over more spe-
   cific AS, IP address or route space by allowing modify and delete
   privileges regardless of the mnt-by in the object itself.



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   The reclaim attribute provides the means to enforce address lending.
   It allows cleanup in cases where entities cease to exist or as a last
   resort means to correct errors such as parties locking themselves out
   of access to their own objects.  To specify all more specific objects
   the reclaim attribute value should be ``ALL''. To allow finer control
   a set of prefixes can be specified.


   A no-reclaim attribute can be used to provide explicit exceptions.  A
   reclaim attribute can only be added to an existing object if the ad-
   dition of the reclaim attribute does not remove autonomy of existing
   more specific objects that are covered by the new reclaim attribute.



  1.  A reclaim attribute can be added to an existing object if there are
      no existing exact matches or more specific objects overlapped by
      the new reclaim attribute, or

  2.  if the submitter is listed in the maintainer pointed to by the mnt-
      by of the objects which are overlapped, or

  3.  if any overlapped object is listed in a no-reclaim attribute in the
      object where the reclaim is being added.



   Similarly, a submitter may delete a no-reclaim attribute from an ob-
   ject only when that submitter is the only maintainer listed in the
   mnt-by attributes of any overlapped objects.  If the submitter is not
   listed in any of the maintainers pointed to by the mnt-by attributes
   for one or more overlapped object, then the submitter is not permitted
   to delete the no-reclaim attribute.


   If neither a reclaim or no-reclaim attribute is present, then more
   specific objects of a given object cannot be modified by the main-
   tainer of the less specified object unless the maintainer is also
   listed as a maintainer in the more specific object.  However, the ad-
   dition of a new route or inetnum object must pass authentication of
   the largest less specific prefix as part of the authentication check
   described in Section 9.9.


   See Section 10 for a full description of the reclaim and no-reclaim
   attributes.



9.6   Other Objects



   Many of the RPSL ancillary objects have no natural hierarchy the way
   AS numbers, Internet addresses and routes do have a numeric hierarchy.
   Some examples are ``maintainers'', ``people'' and ``role'' objects.
   For these objects, lack of any hierarchy leads to two problems.



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  1.  There is no hierarchy that can be exploited to direct queries to
      alternate registries.  At some point the query strategy of search-
      ing all known registries becomes impractical.

  2.  There is no hierarchy on which authorizations of additions can be
      based.



   The first problem can be addressed by considering the name space
   for each of the ancillary objects to be unique only within the lo-
   cal database and to use explicit references to an external repository
   where needed.  To specify an external repository reference, the ob-
   ject key is preceded by the name of the repository and the delimiter
   ``::''.  For example a NIC handle may take the form ``RIPE::CO19''.
   Currently there is a desire to keep NIC handles unique so the nam-
   ing convention of appending a dash and the repository name is used.
   Prepending the repository name provides the unique name space since an
   object in the RIPE database referencing ``CO19'' would be interpreted
   as ``RIPE::CO19'' by default, but it would still be possible to query
   or reference ``IANA::CO19''.  There is no possibility of accidentally
   forgetting to adhere to the conventions when making an addition and
   the existing objects are accommodated, including cases where name
   conflicts have already occurred.


   The second problem can be partially addressed by using a referral
   system for the addition of maintainers and requiring that any other
   object be submitted by a registered maintainer.  The referral system
   would allow any existing maintainer to add another maintainer.  This
   can be used in parallel with the addition of other object types to
   support the maintenance of those objects.  For example, when adding
   a subdomain to the ``domain'' hierarchy (in the RIPE repository where
   domains are also handled), even when adding a new domain to a rela-
   tively flat domain such as ``com'', there is already a maintainer for
   the existing domain.  The existing maintainer can add the maintainer
   that will be needed for the new domain in addition to adding the new
   domain and giving the new maintainer the right to modify it.


   An organization gaining a presence on the Internet for the first time
   would be given a maintainer.  This maintainer may list a small number
   of very trusted employees that are authorized to modify the maintainer
   itself.  The organization itself can then add another maintainer list-
   ing a larger set of employees but listing the more restrictive main-
   tainer in the mnt-by attributes of the maintainers themselves.  The
   organization can then add people and role objects as needed and any
   other objects as needed and as authorization permits.



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9.7   Objects with AS Hierarchical Names



   Many RPSL objects do not have a natural hierarchy of their own but al-
   low hierarchical names.  Some examples are the object types ``as-set''
   and ``route-set''.  An as-set may have a name corresponding to no nam-
   ing hierarchy such as ``AS-Foo'' or it may have a hierarchical name of
   the form ``AS1:AS-Bar''.


   When a hierarchical name is not used, authorization for objects such
   as ``as-set'' and ``route-set'' correspond to the rules for objects
   with no hierarchy described in Section 9.6.


   If hierarchical names are used, then the addition of an object must
   be authorized by the aut-num whose key is named by everything to the
   left of the rightmost colon in the name of the object being added.
   Authorization is determined by first using the mnt-lower maintainer
   reference, or if absent, using the mnt-by reference.



9.8   Query Processing



   A query may have to span multiple repositories.  All queries should
   be directed toward a local repository which may mirror the root repos-
   itory and others.  Currently each IRR repository mirrors all others
   repositories.  In this way, the query may be answered by the local
   repository but draw data from others.


   For object types that have a natural hierarchy, such as aut-num, inet-
   num, and route, the search begins at the root database and follows
   the hierarchy.  For objects types that have no natural hierarchy, such
   as maintainer, person, and role objects, the search is confined to a
   default database unless a database is specified.  The default database
   is the same database as an object from which a reference is made if
   the query is launched through the need to follow a reference.  Other-
   wise the default is generally the local database or a default set by
   the repository.  The default can be specified in the query itself as
   described in Section 9.7.


   In searching for an AS, the delegation attribute in AS blocks can be
   consulted, moving the search to data from other repositories.  Eventu-
   ally the AS is either found or the search fails.


   The search for an inetnum is similar.  Less specific inetnums may
   refer the search to other databases.  Eventually the most specific
   inetnum is found and its status (assigned or not assigned) can be
   determined.


   The search for a route is similar except the search may branch to
   more than one repository.  The most specific route in one repository



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   may be more specific than the most specific in another.  In looking
   for a route object it makes sense to return the most specific route
   that is not more specific than the query requests regardless of which
   repository that route is in rather than return one route from each
   repository that contains a less specific overlap.



9.9   Adding to the Database



   The root repository must be initially populated at some epoch with a
   few entries.  An initial maintainer is needed to add more maintain-
   ers.  The referral-by attribute can be set to refer to itself in this
   special case (Section 10 describes the referral-by).  When adding an
   inetnum or a route object an existing exact match or a less specific
   overlap must exist.  A route object may be added based on an exact
   match or a less specific inetnum.  The root repository must be ini-
   tially populated with the allocation of an inetnum covering the prefix
   0/0, indicating that some address allocation authority exists.  Simi-
   larly an initial as-block is needed covering the full AS number range.


   When adding an object with no natural hierarchy, the search for an
   existing object follows the procedure outlined in Section 9.8.


   When adding an aut-num (an AS), the same procedure used in a query is
   used to determine the appropriate repository for the addition and to
   determine which maintainer applies.  The sequence of AS-block objects
   and repository delegations is followed.  If the aut-num does not ex-
   ist, then the submission must match the authentication specified in
   the maintainer for the most specific AS-block in order to be added.


   The procedure for adding an inetnum is similar.  The sequence of inet-
   num blocks is followed until the most specific is found.  The submis-
   sion must match the authentication specified in the maintainer for the
   most specific inetnum overlapping the addition.


   Adding a route object is somewhat more complicated.  The route object
   submission must satisfy two authentication criteria.  It must match
   the authentication specified in the aut-num and the authentication
   specified in either a route object or if no applicable route object is
   found, then an inetnum.


   An addition is submitted with an AS number and prefix as its key.  If
   the object already exists, then the submission is treated as a modify
   (see Section 9.10).  If the aut-num does not exist on a route add,
   then the addition is rejected (see Section B for further discussion
   of tradeoffs).  If the aut-num exists then the submission is checked
   against the applicable maintainer.  A search is then done for the
   prefix first looking for an exact match.  If the search for an exact
   match fails, a search is made for the longest prefix match that is
   less specific than the prefix specified.  If this search succeeds it



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   will return one or more route objects.  The submission must match an
   applicable maintainer in at least one of these route objects for the
   addition to succeed.  If the search for a route object fails, then
   a search is performed for an inetnum that exactly matches the prefix
   or for the most specific inetnum that is less specific than the route
   object submission.  The search for an inetnum should never fail but it
   may return an unallocated or reserved range.  The inetnum status must
   be ``allocated'' and the submission must match the maintainer.


   Having found the AS and either a route object or inetnum, the autho-
   rization is taken from these two objects.  The applicable maintainer
   object is any referenced by the mnt-routes attributes.  If one or more
   mnt-routes attributes are present in an object, the mnt-by attributes
   are not considered.  In the absence of a mnt-routes attribute in a
   given object, the mnt-by attributes are used for that object.  The
   authentication must match one of the authorizations in each of the two
   objects.


   If the addition of a route object or inetnum contains a reclaim at-
   tribute, then any more specific objects of the same type must be ex-
   amined.  The reclaim attribute can only be added if there are no more
   specific overlaps or if the authentication on the addition is present
   in the authorization of a less specific object that already has a re-
   claim attribute covering the prefix range, or if the authentication on
   the addition is authorized for the modification of all existing more
   specific prefixes covered by the addition.



9.10   Modifying or Deleting Database Objects



   When modifying or deleting any existing object a search for the object
   is performed as described in Section 9.8.  If the submission matches
   an applicable maintainer for the object, then the operation can pro-
   ceed.  An applicable maintainer for a modification is any maintainer
   referenced by the mnt-by attribute in the object.  For route and inet-
   num objects an applicable maintainer may be listed in a less specific
   object with a reclaim attribute.


   If the submission is for a route object, a search is done for all
   less specific route objects and inetnums.  If the submission is for
   an inetnum, a search is done for all less specific inetnums.  If the
   submission fails the authorization in the object itself but matches
   the reclaim attribute in any of the less specific objects, then the
   operation can proceed.  Section B contains discussion of the rationale
   behind the use of the reclaim attribute.


   A modification to an inetnum object that adds a reclaim attribute
   or removes a no-reclaim attribute must be checked against all exist-
   ing inetnums that are more specific.  The same check of the reclaim
   attribute that is made during addition must be made when a reclaim



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   attribute is added by a modification (see Section 9.9).


   A deletion is considered a special case of the modify operation.  The
   deleted object may remain in the database with a ``deleted'' at-
   tribute in which case the mnt-by can still be consulted to remove
   the ``deleted'' attribute.



10   Data Format Summaries



   RIPE-181 [2] and RPSL [1] data is represented externally as ASCII
   text.  Objects consist of a set of attributes.  Attributes are name
   value pairs.  A single attribute is represented as a single line with
   the name followed by a colon followed by whitespace characters (space,
   tab, or line continuation) and followed by the value.  Within a value
   all whitespace is equivalent to a single space.  Line continuation is
   supported by a backslash at the end of a line or the following line
   beginning with whitespace.  When transferred, externally attributes
   are generally broken into shorter lines using line continuation though
   this is not a requirement.  An object is externally represented as a
   series of attributes.  Objects are separated by blank lines.


   There are about 80 attribute types in the current RIPE schema and
   about 15 object types.  Some of the attributes are mandatory in cer-
   tain objects.  Some attributes may appear multiple times.  One or
   more attributes may form a key.  Some attributes or sets of attributes
   may be required to be unique across all repositories.  Some of the
   attributes may reference a key field in an object type and may be
   required to be a valid reference.  Some attributes may be used in
   inverse lookups.


   A review of the entire RIPE or RPSL schema would be too lengthy to
   include here.  Only the differences in the schema are described.



10.1   Changes to the RIPE/RPSL Schema



   One new object type and several attributes are added to the RIPE/RPSL
   schema.  There are significant changes to the rules which determine if
   the addition of an object is authorized.


   The new object type is listed below.  The first attribute listed is
   the key attribute and also serves as the name of the object type.



     as-block         key  mandatory  single     unique
     descr                  optional    multiple



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     remarks                optional    multiple
     admin-c                mandatory  multiple
     tech-c                 mandatory  multiple
     notify                 optional    multiple
     mnt-by                 mandatory  multiple
     changed                mandatory  multiple
     source                 mandatory  single



   In the above object type only the key attribute ``as-block'' is new:



   as-block   This attribute provides the AS number range for an ``as-
      block'' object.  The format is two AS numbers including the sub-
      string ``AS'' separated by a ``-'' delimiter and optional whites-
      pace before and after the delimiter.



   In order to support stronger authentication, the following keywords
   are added to the ``auth'' attribute:



   pgp-from   The remainder of the attribute gives the string identify-
      ing a PGP identity whose public key is held in an external keyring.
      The use of this method is deprecated in favor of the ``pgpkey''
      method.

   pgpkey  See [21].



   In order to disable authentication and give permission to anyone, the
   authentication method ``none'' is added.  It has no arguments.


   An additional change is the ``auth'' attribute is allowed to exist
   in a ``person'' or ``role'' object.  The ``auth'' method ``role'' or
   ``person'' can be used to refer to a role or person object and take
   the ``auth'' fields from those objects.  Care must be taken in imple-
   mentations to detect circular references and terminate expansion or
   the references already visited.


   A few attributes are added to the schema.  These are:



   mnt-routes   The mnt-routes attribute may appear in an aut-num, inet-
      num, or route object.  This attribute references a maintainer ob-
      ject which is used in determining authorization for the addition of
      route objects.  After the reference to the maintainer, an optional



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      list of prefix ranges (as defined in RPSL) inside of curly braces
      or the keyword ``ANY'' may follow.  The default, when no additional
      set items are specified is ``ANY'' or all more specifics.  The mnt-
      routes attribute is optional and multiple.  See usage details in
      Section 9.1.

   mnt-lower   The mnt-lower attribute may appear in an inetnum, route,
      as-block or aut-num object.  This attribute references a maintainer
      object.  When used in an inetnum or route object the effect is the
      same as a ``mnt-routes'' but applies only to prefixes more specific
      than the prefix of the object in which it is contained.  In an as-
      block object, mnt-lower allows addition of more specific as-block
      objects or aut-num objects.  In an aut-num object the mnt-lower at-
      tribute specifies a maintainer that can be used to add objects with
      hierarchical names as described in Section 9.7.

   reclaim   The reclaim attribute may appear in as-block, aut-num, inet-
      num, or route objects.  Any object of the same type below in the
      hierarchy may be modified or deleted by the maintainer of the ob-
      ject containing a reclaim attribute.  The value of the attribute is
      a set or range of objects of the same type where the syntax of the
      set or range is as defined in RPSL. See Section 9.5 for restric-
      tions on adding reclaim attributes.

   no-reclaim   The no-reclaim attribute is used with the reclaim at-
      tribute.  The no-reclaim attribute negates any reclaim attribute it
      overlaps.  See Section 9.5 for restrictions on deleting no-reclaim
      attributes.

   referral-by   This attribute is required in the maintainer object.  It
      may never be altered after the addition of the maintainer.  This
      attribute refers to the maintainer that created this maintainer.
      It may be multiple if more than one signature appeared on the
      transaction creating the object.

   auth-override   An auth-override attribute can be added, deleted, or
      changed by a transaction submitted by maintainer listed in the
      referral-by.  An auth-override can only be added to a maintainer
      if that maintainer has been inactive for the prior 60 days.  The
      auth-override attribute itself contains only the date when the at-
      tribute will go into effect which must be at least 60 days from the
      current date unless there is already authorization to modify the
      maintainer.  After the date in the auth-override is reached, those
      identified by the maintainer in the referral-by have authoriza-
      tion to modify the maintainer.  This attribute exists as a means to
      clean up should the holder of a maintainer become unresponsive and
      can only take effect if that maintainer does not remove the auth-
      override in response to the automatic notification that occurs on
      changes.



   Each repository must identify itself with a ``repository'' object.
   The repository must also contain a special ``repository'' whose key



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   is ``ROOT''. The root repository is where all non-local queries are
   directed, including where hierarchical object queries start.  The
   query methods listed for the root repository may actually be a subset
   of those offered by that repository if efficiency considerations and
   topologic distance make some methods less useful.


   The root repository must contain a copy of the repository objects
   in any repository considered valid.  The repository objects will be
   essential when the routing registry becomes more widely distributed.


   The existing ``mnt-by'' attribute references the ``maintainer'' ob-
   ject type.  The ``mnt-by'' attribute is now mandatory in all object
   types.  A new maintainer may be added by any existing maintainer.  The
   ``referral-by'' attribute is now mandatory in the ``maintainer'' ob-
   ject to keep a record of which maintainer made the addition and can
   never be changed.  Maintainers cannot be deleted as long as they are
   referenced by a ``referral-by'' attribute elsewhere.



A   Examples



   The examples below leave out some required attributes that are not
   needed to illustrate the use of the objects and attributes described
   in this document.  Missing are admin-c, tech-c, changed, source.  Also
   missing are attributes such as mnt-nfy, whose use are a good practice
   but are not strictly required.


   To do anything at all a maintainer is needed.  At some epoch a a sin-
   gle maintainer is populated in one repository and that maintianer has
   a referal-by pointing to itself.  All others referal-by references
   can be traced back to that maintainer.  At the epoch the as-block AS0-
   AS65535 and the inetnum 0.0.0.0-255.255.255.255 are also allocated.
   Other ancilliary object may also be needed to bootstrap.



       mntner:         ROOT-MAINTAINER
       auth:           pgpkey PGP-12345678
       mnt-by:         ROOT-MAINTAINER
       referal-by:     ROOT-MAINTAINER



   This root maintainer might add a top level maintainer for some organi-
   zation.



       mntner:         WIZARDS



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       descr:          High level Technical Folks
       auth:           pgpkey PGP-23456789
       auth:           pgpkey PGP-3456789a
       mnt-by:         WIZARDS
       referal-by:     ROOT-MAINTAINER



   That maintainer might add another who have more limited capabilities.



       mntner:         MORTALS
       descr:          Maintain day to day operations
       auth:           pgpkey PGP-456789ab
       auth:           pgpkey PGP-56789abc
       auth:           pgpkey PGP-6789abcd
       mnt-by:         WIZARDS
       referal-by:     WIZARDS



   Note that the WIZARDS can change their own maintainer object and the
   MORTALS maintainer object but MORTALS cannot.


   At some point an as-block is allocated and broken down.  In the exam-
   ple below, private number space is used.



       as-block:       AS65500-AS65510
       mnt-by:         SOME-REGISTRY
       mnt-lower:      WIZARDS



   Note that a registry has control over the object that they have cre-
   ated representing the allocation, but have given the party to which
   the allocation was made the ability to create more specific objects.
   Below this as-block, an aut-num is added.  Note that import and export
   are normally required for a aut-num but are not shown here.



       aut-num:        AS65501
       mnt-by:         WIZARDS
       mnt-lower:      MORTALS



   In aut-num above the WIZARDS maintainer can modify the aut-num itself.



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   The MORTALS maintainer can add route objects using this AS as the ori-
   gin if they also have authorization for the IP number space in a less
   specific route or inetnum.


   We also need an inetnum allocation.  In this example the inetnum is
   allocated to a completely different organization.  Again attributes
   are omited which would normally be needed in an inetnum.



       inetnum:        192.168.144.0-192.168.151.255
       mnt-by:         SOME-REGISTRY
       mnt-lower:      ISP
       reclaim:        ALL



   The maintainer ISP can add more specific inetnums or routes with this
   address space.  Note that the registry has declared their ability to
   reclaim the address space.


   If ISP wished to reclaim all allocations but some suballocation of
   theirs resisted, we might get something like the following in which
   they will reclaim only the top half of an allocation (possibly if it
   remains unused).



       inetnum:        192.168.144.0-192.168.147.255
       mnt-by:         ISP
       mnt-lower:      EBG-COM
       reclaim:        192.168.146/23+



   If we assume that the maintainer EBG-COM and the maintainer MORTALS
   want to add a route object, one way to do it is for both parties to
   sign.  If EBG-COM for some reason couldn't aggregate an allocate a
   single top level route (which is inexcusable these days) or there was
   a preference for some reason to avoid the joint signature approach on
   a submission either party could give the other permission to make the
   addition.  A mnt-routes could be added to the aut-num or a mnt-lower
   could be added to an inetnum.



       aut-num:        AS65501
       mnt-by:         WIZARDS
       mnt-lower:      MORTALS
       mnt-routes:     EBG-COM -192.168.144/23"



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   With this change to the aut-num the maintainer EBG-COM could add a
   route with origin AS65501, but only with a limited address range.



       route:          192.168.144/24
       origin:         AS65501
       descr:          These boneheads don't aggregate
       mnt-by:         EBG-COM
       mnt-by:         FICTION::MORTALS



   Note that while the maintainer EBG-COM added the object they allowed
   the maintainer MORTALS the ability to modify it.


   If an object ended up in another repository, a single maintainer could
   still be used.  In the example above the notation FICTION::MORTALS in-
   dicates that the route object is in a different repository and rather
   than duplicate the maintainer, a reference is made to the repository
   in which the MORTALS object resides.


   In the example below, a pair of route-sets are added and hierarchical
   names are used.



       route-set:      AS65501:Customers
       mnt-by:         WIZARDS
       mnt-lower:      MORTALS


       route-set:      AS65501:Customers:EBG-COM
       mnt-by:         MORTALS
       mnt-lower:      EBG-COM



   Suppose in the 192.168.144/24 object above, only the EBG-COM main-
   tainer is listed.  If EBG-COM goes bankrupt, no longer needs address
   space, and stops responding, it could be difficult to delete this
   object.  The maintainer listed in the EBG-COM referral-by attribute
   could be contacted.  They could add a auth-override attribute to the
   EBG-COM object.  Later they could modify the EBG-COM object and then
   any objects with EBG-COM in the mnt-by.



       mntner:         EBG-COM
       mnt-by:         EBG-COM
       auth-override: 19990401



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   The examples above stray significantly from realism.  They do provide
   simple illustrations of the usage of the objects type and attributes
   described in this document and hopefully in doing some are of some
   value.



B   Technical Discussion



   A few design tradeoffs exist.  Some of these tradeoffs, the selected
   solution, and the alternatives are discussed here.  Some of the issues
   are listed below.



  1.  Whether to error on the side of permissiveness and weaken autho-
      rization controls or risk the possibility of erecting barriers to
      registering information.

  2.  Whether to support enforcible address lending or provide the
      smaller or end user with ultimate control over the registration
      of the prefixes they are using.

  3.  What to do with older objects that either don't conform to newer
      requirements regarding minimum authorization, authentication, and
      accountability, or are of questionable validity.



B.1   Relaxing requirements for ease of registry



   If the requirement that an aut-num exists is relaxed, then it is pos-
   sible for anyone to make use of an unassigned AS number or make use
   of an assigned AS number for which the aut-num has not been entered.
   Placing requirements on the entry of aut-num presumes cooperation of
   the Internet address allocation authority (if separate from the rout-
   ing registry).  The address allocation authority must be willing to
   field requests to populate skeleton aut-nums from the party for which
   the allocation has been made.  These aut-num must include a reference
   to a maintainer.  A request to the address allocation authority must
   therefore include a reference to an existing maintainer.


   The ability to add route objects is also tied to the existence of less
   specific route objects or inetnums.  The Internet address allocation
   authority (if separate from the routing registry) must also be will-
   ing to field requests to add inetnum records for the party already
   allocated the address space.


   The Internet address allocation authority should also add inetnums and
   aut-nums for new allocations.  In order to do so, a maintainer must
   exist.  If a party is going to connect to the Internet, they can get a



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   maintainer by making a request to the Internet service provider they
   will be connecting to.  Once they have a maintainer they can make a
   request for address space or an AS number.  The maintainer can con-
   tain a public key for a cryptographicly strong authorization method
   or could contain a ``crypt-key'' or ``mail-to'' authorization check if
   that is considered adequate by the registering party.  Furthermore an
   address allocation authority should verify that the request for an AS
   number or for address space matches the authorization criteria in the
   maintainer.


   Currently only the registry themselves may add maintainers.  This be-
   comes a problem for the registry particularly verifying public keys.
   This requirement is relaxed by allowing existing maintainers to add
   maintainers.  Unfortunately the accountability trail does not exist
   for existing maintainers.  The requirement then should be relaxed
   such that existing maintainers may remain but only existing maintain-
   ers that have a ``referral-by'' attribute can add maintainers.  The
   ``referral-by'' cannot be modified.  This requirement can be relax
   slightly so that a ``referral-by'' can be added to a maintainer by
   an existing maintainer with a ``referral-by''.  This will allow the
   accountability trail to be added to existing maintainers and these
   maintainers can then add new maintainers.


   Verifying that a party is who they claim to be on initial addition,
   is one of the problems that currently falls upon the AS number and
   address registry.  This problem is reduced by allowing existing main-
   tainers to add maintainers.  This may actually make it easier to get
   maintainers and therefore easier to register.  The number authority
   still must verify that the AS or address space is actually needed by
   the party making a request.


   Authorization checks made during the addition of route objects that
   refer to AS objects and inetnum strongly rely on the cooperation of
   the Internet address allocation authorities.  The number authorities
   must register as-blocks, aut-nums, or inetnums as AS numbers or ad-
   dress space is allocated.  If only a subset of the number authorities
   cooperate, then either an inetnum or as-block can be created cover-
   ing the space that registry allocates and essentially requiring null
   allocation (for example a ``crypt-pw'' authentication where the pass-
   word is given in the remarks in the object or its maintainer) or those
   obtaining addresses from that number authority will have trouble reg-
   istering in the routing registry.  The authorization model supports
   either option, though it would be preferable if the number authorities
   cooperated and the issue never surfaced in practice.


   The maintainer requirements can be relaxed slightly for existing main-
   tainers making it easier to register.  Relaxing requirements on other
   objects may defeat the authorization model, hence is not an option.



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B.2   The address lending issue



   The issue of whether lending contracts should be enforcible is an
   issue of who should ultimately be able to exercise control over al-
   locations of address space.  The routing registry would be wise to
   stay as neutral as possible with regard to disputes between third par-
   ties.  The ``reclaim'' and ``no-reclaim'' are designed to allow either
   outcome to the decision as to whether the holder of a less specific
   inetnum or route object can exercise control over suballocations in
   the registry.  The routing registry itself must decide whether to re-
   tain control themselves and if so, should very clearly state under
   what conditions the registry would intervene.  A registry could even
   go to the extreme of stating that they will intervene in such a dis-
   pute only after the dispute has been resolved in court and a court
   order has been issued.


   When an allocation is made by a registry, the registry should keep a
   ``reclaim'' attribute in the less specific object and make a strong
   policy statement that the reclaim privilege will not be used except
   under very clearly defined special circumstances (which at the very
   minimum would include a court order).  If the allocation is further
   subdivided the party subdividing the allocation and the party accept-
   ing the suballocation must decide whether a ``reclaim'' can be kept by
   the holder of the less specific allocation or whether a ``no-reclaim''
   must be added transferring control to the holder of the more specific.
   The registry is not involved in that decision.  Different pairs of
   third parties may do different decisions regarding the ``reclaim''
   and any contractual restrictions on its use that may be expressed out-
   side of the registry in the form of a legal contract and ultimately
   resolved by the courts in the event of a bitter dispute.


   By retaining ``reclaim'' rights the registry retains the ability to
   abide by a court order.  This may only truly become an issue in a dis-
   tributed registry environment where registries will be rechecking the
   authorization of transactions made elsewhere and may fail to process
   the attempt of another registry to abide by a court order by overrid-
   ing normal authorization to change the registry contents if a reclaim
   is not present.



B.3   Dealing with non-conformant or questionable older data



   Some of the newer requirements include requiring that all objects
   reference a maintainer object responsible for the integrity of the
   object and requiring accountability for the creation of maintainers
   to be recorded in the maintainer objects so that accountability can
   be traced back from an unresponsive maintainer.  In the event that
   contact information is absent or incorrect from objects and there is
   any question regarding the validity of the objects, the maintainer can



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   be contacted.  If the maintainer is unresponsive, the maintainer that
   authorized the addition of that maintainer can be contacted to either
   update the contact information on the maintainer or confirm that the
   entity no longer exists or is no longer actively using the Internet or
   the registry.


   Many route objects exist for which there are no maintainers and for
   which inetnum and AS objects do not exist.  Some contain the now obso-
   leted guardian attribute rather than a mnt-by.


   It is not practical to unconditionally purge old data that does not
   have maintainers or does not conform to the authorization hierarchy.
   New additions must be required to conform to the new requirements
   (otherwise the requirements are meaningless).  New requirements can
   be phased in by requiring modifications to conform to the new require-
   ments.


   A great deal of questionable data exists in the current registry.  The
   requirement that all objects have maintainers and the requirements
   for improved accountability in the maintainers themselves may make it
   easier to determine contact information even where the objects are not
   updated to reflect contact information changes.


   It is not unreasonable to require valid contact information on exist-
   ing data.  A great deal of data appears to be unused, such as route
   objects for which no announcement has been seen in many months or
   years.  An attempt should be made to contact the listed contacts in
   the object, in the maintainer if there is one, then up the maintainer
   referral-by chain if there is one, and using the number registry or
   origin AS contact information if there is no maintainer accountability
   trail to follow.  Experience so far indicates that the vast majority
   of deletions identified by comparing registered prefixes against route
   dumps will be positively confirmed (allowing the deletion) or there
   will be no response due to invalid contact information (in many cases
   the IRR contact information points to nsfnet-admin@merit.edu).


   By allowing the registry to modify (or delete) any objects which are
   disconnected from the maintainer accountability trail, cleanup can
   be made possible (though mail header forging could in many cases have
   the same effect it is preferable to record the fact that the registry
   itself made the cleanup).  Similarly, a mechanism may be needed in
   the future to allow the maintainer in the referral-by to override
   maintainer privileges in a referred maintainer if all contacts have
   become unresponsive for a maintainer.  The referral-by maintainer is
   allowed to add an ``auth-override'' attribute which becomes usable
   as an ``auth'' within 60 days from the time of addition.  The main-
   tainer themselves would be notified of the change and could remove the
   ``auth-override'' attribute before it becomes effective and inquire as
   to why it was added and correct whatever problem existed.  This can be
   supported immediately or added later if needed.



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C   Common Operational Cases



   In principle address allocation and route allocation should be hierar-
   chical with the hierarchy corresponding to the physical topology.  In
   practice this is often not the case for numerous reasons.  The pri-
   mary reasons are the topology is not strictly tree structured and the
   topology can change.  More specificly:



  1.  The Internet topology is not strictly tree structured.

      o  At the top level the network more closely resembles a moderately
         dense mesh.

      o  Near the bottom level many attachments to the Internet are multi-
         homed to more than one Internet provider.

  2.  The Internet topology can and does change.

      o  Many attachments switch providers to obtain better service or
         terms.

      o  Service providers may modify adjacencies to obtain better transit
         service or terms.

      o  Service providers may disappear completely scattering attachments
         or merge.



   Renumbering is viewed as a practical means to maintain a strict nu-
   meric hierarchy [18].  It is also acknowledged that renumbering IPv4
   networks can be difficult [18, 3, 19 ].  We examine first the simple
   case where hierarchy still exists.  We then examine the operational
   cases where either initial topology is not tree structured or cases
   where topology changes.



C.1   simple hierarchical address allocation and route allocation



   This is the simplest case.  Large ranges of inetnums are assigned to
   address registries.  These registries in turn assign smaller ranges
   for direct use or to topologically large entities where allocations
   according to topology can reduce the amount of routing information
   needed (promote better route aggregation).


   AS objects are allocated as topology dictates the need for additional
   AS [10].  Route objects can be registered by those with authoriza-
   tion given by the AS and by the address owner.  This is never an issue
   where the maintainer of the AS and the inetnum are the same.  Where
   they differ, either the provider can give permission to add route ob-
   jects for their AS, or the party allocated the address space can give



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   the provider permission to add router objects for their address space,
   or both parties can sign the transaction.  Permission is provided by
   adding to maintainer attributes.



C.2   aggregation and multihomed more specific routes



   Aggregation is normally not a problem if a provider is aggregating ad-
   dress space allocated to the provider and then suballocated internally
   and/or to customers.  In fact, the provider would be expected to do
   so.  This is not a problem even if the route object for the aggrega-
   tion is added after the more specific route objects since only less
   specific objects are considered.


   Aggregation is potentially a problem if a provider or a set of
   providers plan to aggregate address space that was never explicitly
   allocated as a block to those providers but rather remains the alloca-
   tion of a address registry.  These large aggregations can be expected
   to be uncommon, but relatively easily dealt with.  Superaggregates of
   this type will generally be formed by topologically close entities who
   have also managed to draw adjacent address allocations.  In effect,
   the registry must give permission to form such as superaggregate by
   either giving permission to do so in the mnt-routes of an inetnum or
   by signing the submission along with the other parties.



C.3   provider independent addresses and multiple origin AS



   Provider independent addresses and multihoming arrangement using mul-
   tiple origin AS present a similar problem to multihoming.  The main-
   tainer of the address space and the maintainer of the AS is not the
   same.  Permission can be granted using mnt-routes or multiple signa-
   tures can appear on the submission.



C.4   change in Internet service provider



   A change in Internet service providers is similar to multihoming.
   A minor difference is that the AS for the more specific route will
   be the AS of the new provider rather than the AS of the multihomed
   customer.  Permission can be granted using mnt-routes or multiple
   signatures can appear on the submission.



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C.5   renumbering grace periods



   Renumbering grace periods allow a provider who wants to keep an ad-
   dress allocation intact to allow a customer who has chosen to go to
   another provider to renumber their network gradually and then re-
   turn the address space after renumbering is completed.  The issue of
   whether to require immediate renumbering or offer renumbering grace
   periods and how long they should be or whether they should be in-
   definite has been topic of bitter disputes.  The authorization model
   can support no renumbering grace period, a finite renumbering grace
   period, or an indefinite renumbering grace period.  The ``reclaim''
   attribute described in Section 9.1 provides a means to end the grace
   period.



D   Deployment Considerations



   This section describes deployment considerations.  The intention is to
   raise issues and discuss approaches rather than to provide a deploy-
   ment plan.


   The use of routing registries is not yet universally accepted.  There
   still remain Internet providers who see no reason to provide the added
   assurance of accurate routing information described in Section 6.
   More accurately, these benefits are viewed as being insufficient to
   justify the cost.  This has been largely caused an inability of a very
   major router vendor up until recently to handle prefix lists of the
   size needed to specify routing policy on a per prefix basis.  Another
   reason cited is that filtering on a prefix basis in an environment
   where routing registry is incomplete or inaccurate can interfere with
   connectivity.


   There clearly is a critical mass issue with regard to the use of rout-
   ing registries.  A minority of providers use the existing IRR to
   filter on a per prefix basis.  Another minority of providers do not
   support the IRR and generally fail to register prefixes until con-
   nectivity problems are reported.  The majority of providers register
   prefixes but do not implement strict prefix filtering.


   Deploying new authentication mechanisms has no adverse consequences.
   This has been proven with Merit's deployment of PGP.


   In deploying new authorization mechanisms, a major issue is dealing
   with existing data of very questionable origin.  A very large num-
   ber of route objects refer to prefixes that have not been announced
   for many years.  Other route objects refer to prefixes that are no
   longer announced with the origin AS that they are register with (some
   were incorrectly registered to start with).  There are many causes for
   this.



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  1.  During the transition from the NSFNET PRDB to the RADB a large
      number of prefixes were registered with an origin AS correspond-
      ing to the border AS at which the NSFNET had once heard the route
      announcements.  The PRDB did not support origin AS, so border
      AS was used.  Many of these routes were no longer in use at the
      time and are now routed with a submitter listed as ``nsfnet-
      admin@merit.edu''.

  2.  As CIDR was deployed, aggregates replaced previously separately
      announced more specific prefixes.  The route objects for the more
      specific prefixes were never withdrawn from the routing registries.

  3.  Some prefixes are simply no longer in use.  Some networks have been
      renumbered.  Some network no longer exist.  Often the routing reg-
      istry information is not withdrawn.

  4.  As provider AS adjacencies changed and as end customers switched
      providers often the actual origin AS changed.  This was often not
      reflected by a change in the routing registry.



   Inaccuracies will continue to occur due to the reasons above, except
   the first.  The hierarchical authorization provides greater account-
   ability.  In the event that the contacts for specific objects become
   unresponsive traversal up the authorization hierarchy should help
   identify the parties having previous provided authorization.  These
   contacts may still have sufficient authorization to perform the neces-
   sary cleanup.  This issue is discussed in Section B.


   A great deal of information is currently missing in the IRR. Quite a
   few AS have no aut-num.  Quite a lot of data has no maintainer and the
   vast majority of maintainers use only the weakest of authentication
   methods.  Very little can be done by the registries to correct this.
   The defaults in the cases of missing objects needed for authorization
   has to be to make no authentication checks at all.


   The transition can be staged as follows:



  1.  Add and make use of stronger authorization models.

  2.  Make schema modifications necessary to support delegations.

  3.  Add delegation objects needed for query traversal.

  4.  Base query traversal on delegations rather than search of all known
      registries.

  5.  Obtain the cooperation of the address registries for the purpose of
      populating the ``inetnum'' entries on an ongoing basis.

  6.  Add hierarchical authorization support for critical object types,
      ``aut-num'', ``inetnum'' and ``route''.



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  7.  Add the requirement that database object either be in use or have
      valid contact information and if queries are made by the registry a
      response from a contact indicating that the object serves a purpose
      if it is not clear what its use is.

  8.  Begin to purge data which is clearly not in use and for which there
      is no valid contact information or no response from the contacts.



   Deployment of hierarchical authorization requires cooperation among
   the existing routing registries.  New code will have to be deployed.
   In some cases very little development resources are available and sub-
   stantial inertia exists due to the reliance on the current repository
   and the need to avoid disruption.


   If hierarchical authorization of route objects depends on the exis-
   tence of address registration information, minimal cooperation of
   the currently separate address registries is required.  The extent
   of the cooperation amounts to sending cryptographically signed trans-
   actions from the address registry to the number registry as address
   allocations are made or providing equivalent access to new address
   allocations.


   Currently most registries returns query results from all of the known
   repositories using their mirrored copies.  Cross registry authoriza-
   tions are not yet implemented.  Minimal schema changes have to be made
   to support the ability to delegate objects for which there is an au-
   thorization hierarchy and the support queries and references to other
   repositories.  In the case of AS delegations, ``as-block'' need to be
   created solely for the purpose of traversal.



E   Route Object Authorization Pseudocode



   The following list provides a brief review of basic concepts.



  1.  The route object submission must satisfy two authentication cri-
      teria.  It must match the authentication specified in the aut-num
      and the authentication specified in either a route object or if no
      applicable route object is found, then an inetnum.

  2.  When checking for prefix authorization, an exact route object pre-
      fix match is checked for first.  If there is not an exact match
      then a longest prefix match that is less specific than the prefix
      is searched for.  If the route prefix search fails, then a search
      is performed for an inetnum that exactly matches the prefix or for
      the most specific inetnum that is less specific than the route ob-
      ject submission.



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      The search for an inetnum should never fail but it may return an
      unallocated or reserved range.  The inetnum status must be ``allo-
      cated'' and the submission must pass it's maintainer authorization
      in order to get authorization from an inetnum.  So an unallocated
      or reserved range inetnum will cause the route object submission to
      fail.

  3.  A route object must pass authorization from both the referenced
      aut-num object and the route or inetnum object.

      Authorization shall be tested using the maintainer(s) referenced
      in the ``mnt-routes'' attribute(s) first.  If that check fails,
      the ``mnt-lower'' attributes are checked.  If that check fails the
      ``mnt-by'' attributes are used for the authorization check.

  4.  The ``reclaim'' attribute can appear in inetnum, route and as-block
      objects and provides a means to support address lending.  ``re-
      claim'' gives authorization over more specific objects, regardless
      of the ``mnt-by'' in the object.  The value of a ``reclaim'' at-
      tribute can be a list or set of objects to provide finer grain
      control.

      The ``reclaim'' attribute is important to this discussion since
      it affects prefix/origin authentication when a new route object is
      submitted.

      The ``no-reclaim'' attribute is used to provide explicit excep-
      tions.



   The following pseudocode outlines the algorithm used to check for
   proper authorization of a route object submission.



     Case #1.  Route object add
                (ie, no exact prefix/origin match exists).


     /* first check the aut-num authorization */


     if ( the referenced aut-num object does not exist or
           the aut-num authorization fails )
       authorization fails


     /* next we check for prefix authorization */


     if ( a less specific route(s) with the longest prefix is found ) [
       if ( authorization does not pass for at least one of the less
             specific route(s) )
          authorization fails


     /* now check for a "reclaim" attr */



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       if ( the object has a "reclaim" attribute ) [
          if ( no more-specifics exist
               OR a less specific exists which passes
                  authorization and has a "reclaim" attribute
               OR all more specifics routess pass modify authorization )
            authorization passes
          else
            authorization fails
       ] else
          authorization passes
     ]


     /* there are no less specific routes to check for prefix
         authentication, so we need to try and get authorization from an
         inetnum object */


     if ( ( an inetnum is found that is an exact match
             OR is less specific and it's status is "allocated" )
           AND a maintainer referenced by the inetnum
               passes authorization )
       authorization succeeds


     /* if there is no inetnum or route object then then
         authorization fails.  This should never happen if
         the DB is initialized properly. */


     authorization fails.



     Case #2.  Route object modify/delete
                (ie, exact prefix/origin match exists).


     if ( the mnt-by passes authorization )
       authorization succeeds


     /* if the authorization did not pass from the matched object,
         we can still get authorization from a less specific route if it
         has a "reclaim" attribute and we pass authorization */


     if ( a less specific route or inetnum object passes authorization
           AND has a "reclaim" attribute applicable to
               the object to be modified )
       authorization succeeds
     else
       authorization fails



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Acknowledgments



   This document draws ideas from numerous discussions and contributions
   of the IETF Routing Policy System Work Group and RIPE Routing Work
   Group.  Earlier drafts of this document listed Carol Orange as a co-
   author.  Carol Orange made contributions to this document while at
   RIPE.


   Gerald Winters provided the pseudocode in an email message to the
   RIPE dbsec mailing list that was the basis of the pseudocode found in
   appendix E.



References



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   [13]  David Meyer, Mark Prior, Cengiz Alaettinoglu, J. Schmitz, and
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   [21]  Janos Zsako.         Pgp authentication for ripe database updates.
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         authent-00.txt.



Security Considerations



   This document primarily addresses authorization rules for making ad-
   ditions, deletions, and changes to routing policy information repos-
   itories.  The authentication of these transactions through strong
   cryptographic means are addressed by [21], referenced thorughout this
   document.  The authorization rules are designed such that the inte-
   grety of any transaction can be verified independently by any party
   mirroring a repository to insure that rules are adhered to.  To accom-
   plish this the mirror must contain data already known to be properly
   authorized.  In other words, the mirror must be complete and authenti-
   cation and authorization checks must be made continuously as changes
   to the repository are recieved and processed in order.


   Authentication alone does not provide a complete security model.  Cur-
   rent practice specifies authorization for deletions and changes only,
   not for additions.  The authorization rules provide here complete
   the security model for additions, deletions, and changes by very ex-
   plicitly defining rules for addition and clarifying procedures for
   handling exception cases such as organizations which have ceased to
   exist and therefore become entirely unresponsive.


   Authentication and authorization of queries is explicitly stated to be
   out of scope of this document.



Author's Addresses



   Curtis Villamizar
   UUNET Network Architecture Group
   <curtis@ans.net>



   Cengiz Alaettinoglu
   ISI
   <cengiz@ISI.EDU>



   David M. Meyer



Villamizar, et.  al.           Expires  October 22, 1999           [Page 39]


INTERNET-DRAFT          Routing Policy System Security         April 22, 1999



   Cisco
   <dmm@cisco.com>



   Sandy Murphy
   Trusted Information Systems
   <sandy@tis.com>



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Villamizar, et.  al.           Expires  October 22, 1999           [Page 40]