Internet Engineering Task Force Curtis Villamizar INTERNET-DRAFT ANS draft-ietf-rps-auth-01 Cengiz Alaettinoglu ISI David M. Meyer University of Oregon Sandy Murphy TIS Carol Orange RIPE May 15, 1998 Routing Policy System Security Status of this Memo This document is an Internet-Draft. 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 material or to cite them other than as ``work in progress.'' To view the entire list of current Internet-Drafts, please check the "1id-abstracts.txt" listing contained in the Internet-Drafts Shadow Directories on ftp.is.co.za (Africa), ftp.nordu.net (Northern Europe), ftp.nis.garr.it (Southern Europe), munnari.oz.au (Pacific Rim), ftp.ietf.org (US East Coast), or ftp.isi.edu (US West Coast). Abstract The RIPE database specifications [2] and RPSL language [1] 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 exchanging 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 INTERNET-DRAFT Routing Policy System Security May 15, 1998 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 [18]. 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 in- formation. 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 requirement 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. 2 Background An early routing policy system used in the T3--NSFNET, the policy routing database (PRDB), provided a means of determining who was Villamizar, et. al. Expires November 15, 1998 [Page 2] INTERNET-DRAFT Routing Policy System Security May 15, 1998 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. The need to represent the routing policies of many organizations, 2. CIDR and overlapping prefixes, the increasing complexity of routing policies and the needs of aggregation, 3. the need to assure integrity of the data and delegate authority for the data representing specifically allocated resources to multiple persons or organizations, 4. the 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 [2]. Its predecessor, the PRDB, addressed the needs of a single organization, while the RIPE database was initially intended to address the needs of the European Internet community. The RIPE database formats as described in [2] are the basis of current IRR. Routing protocols themselves provide no assurance that the origination of a route is legitimate and can actually reach the stated destination. The nature of CIDR allows more specific prefixes to override less specific prefixes [9, 19, 8]. Even with signed route origination, there is no way to determine if a more specific prefix is legitimate 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, 15, 14] was a fairly substantial evolutionary step in the data representation which was largely targeted at addressing the second group of needs. The PRDB accommodated CIDR in 1993 [13] and the RIPE database accommodated the entry of CIDR prefixes from inception, but RPSL provides many needed improvements including explicit support for aggregation. Transition of the IRR to RPSL is expected to occur in late 1988 [12]. This document addresses the third group of needs identified above. Villamizar, et. al. Expires November 15, 1998 [Page 3] INTERNET-DRAFT Routing Policy System Security May 15, 1998 While the current implementation supporting weak authentication doesn't guarantee integrety 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 inaddequate 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 developed to prevent such problems before they happen. A separate document addressing the fourth group of needs is also being written. 3 Implicit Policy Assumptions The authorization model encodes certain policies for allocation of address numbers, AS numbers, and for the announcement of routes. Implicit to the authorization model are a very limited number of policy assumptions. 1. Address numbers are allocated hierachically. 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 registries. Registries are allocated blocks of AS numbers, thereby making the allocation hierarchical. 3. Routes should only be anounced 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 addresses, 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 authentication mechanism is used, all involved parties can be notified about the changes that occurred through use of the existing ``notify'' attribute. Villamizar, et. al. Expires November 15, 1998 [Page 4] INTERNET-DRAFT Routing Policy System Security May 15, 1998 4 Organization of this Document Familiarity with RIPE-181 [2] and RPSL [1] is assumed throughout this document. Goals are described in Section 5. Section 6 through Section 8 provide descriptions of the changes and discussion. Section 9 provides a concise summary of data formats and semantics. Appendix A through Appendix C provide additional technical discussion, examples, and deployment considerations. Goals and Requirements Section 5 provides a more detailed description 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 6 provides some characteristics of RPSL and formats for external representations of information. Authentication Model Section 7 describes current practice, proposes additional authentication methods, and describes the extension mechanism if additional methods are needed in the future. Authorization Model Section 8 describes the means of determining whether a transaction contains the authorization needed to add, modify, or delete specific data objects, based on stated authentication requirements in related data objects. Data Format Summaries Section 9 provides a concise reference to the data formats and steps in transaction processing. Technical Discussion Section A contains some discussion of technical tradeoffs. Common Operational Cases Section B provides some examples drawn from past operational experience with the IRR. Deployment Considerations Section C describes some deployment issues and discusses possible means of resolution. 5 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 practical. The integrity of routing information is critical in Villamizar, et. al. Expires November 15, 1998 [Page 5] INTERNET-DRAFT Routing Policy System Security May 15, 1998 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 opera- tors. Mistyping can divert traffic from a completely unrelated desti- nation to a router with no actual reachability to the advertised des- tination. This can happen and does happen somewhat regularly. In ad- dition, 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 considerably more rare, on a few occasions where this has occurred the results were catas- trophic. 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 advertisement is valid. Today checks are typically made against the border AS advertising the route. This prevents accepting routes from the set of border AS that could not be 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 prefixes 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 Villamizar, et. al. Expires November 15, 1998 [Page 6] INTERNET-DRAFT Routing Policy System Security May 15, 1998 Internet 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 and localizing the denial of service to that Internet provider only if the immediate 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 distributed [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 allocation. The need for this delegation of authority to numerous registries 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 authorized 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. o Authentication is the means to determine who is attempting to make a change. o Authorization is the determination of whether a transaction passing 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 encryption may not be necessary or may not be legally available. For this reason multiple authentication methods must be supported, selected on a per object basis. The authentication methods may range Villamizar, et. al. Expires November 15, 1998 [Page 7] INTERNET-DRAFT Routing Policy System Security May 15, 1998 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 allocation is a simple numeric hierarchy. Route allocation is somewhat more complicated. The key attributes in a route object (key with regard 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 mul- tiple origin AS values due to a common multihoming practice that does not require a unique origin AS. There is often no correlation between 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 B with discussion of technical tradeoffs in Appendix A. o simple hierarchical address allocation and route allocation o aggregation and multihomed more specific routes o provider independent addresses and multiple origin AS o changing Internet service providers o renumbering grace periods The authorization model must accommodate a variety of policies regarding 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, 20]. 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 A. Villamizar, et. al. Expires November 15, 1998 [Page 8] INTERNET-DRAFT Routing Policy System Security May 15, 1998 6 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 authentication and authorization mechanisms. These additions are very few and are described in Section 7 and Section 8. 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. 7 Authentication Model The maintainer objects serve as a container to hold authentication filters. A reference to a maintainer within another object defines authorization to perform operations on the object or on a set of related 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 8.1. The maintainer contains one or more ``auth'' attributes. Each ``auth'' attribute begins with a keyword identifying the authentication method followed by the authentication information needed to enforce that method. For example, where the method is identified by the keyword ``pgp-key'' the authentication information is the PGP public key block in ASCII radix-64 format. Authentication methods currently supported include the following. Note that pgp-from is being replaced by the pgp-key (see Section 9). Villamizar, et. al. Expires November 15, 1998 [Page 9] INTERNET-DRAFT Routing Policy System Security May 15, 1998 mail-from This is a very weak authentication check and is discouraged. 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 authentication information is a fixed encrypted password in UNIX crypt format. 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 ``pgp-key'' 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. pgp-key The authentication information is a PGP public key block in ASCII radix-64 format. The maintainer is authenticated if the transaction is signed by the corresponding private key. 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 disallow the addition of ``auth'' attributes with the depricated ``pgp-from'' method. Any digital signature technique can be used for authentication. Transactions should be signed using multiple digital signature techniques to allow repositories or mirrors that only use a subset of the techniques to verify at least one of the signatures. Any digital signature techniques would be applicable. One that may be supported in the in the future is DSA [16, 17]. Numerous digital signature algorithms are described in [22]. 8 Authorization Model The authorization model must accommodate the requirements outlined in Section 5. A key feature of the authorization model is the recognition that authorization for the addition of certain types of data objects must be derived from related data objects. Villamizar, et. al. Expires November 15, 1998 [Page 10] INTERNET-DRAFT Routing Policy System Security May 15, 1998 With multiple repositories, objects not found in RPSL are needed to control AS delegations and new attributes are needed in existing objects to control subdelegation. Objects are also needed to provide query information for other repositories. A root repository must be agreed upon. Ideally such a repository would contain only top level delegations and pointers to other repositories used in these delegations. It would be wise to allow only cryptographically strong transactions in the root repository. The following might be used to identify a repository (for formal description, see 9). repository: RIPE query-address: whois.ripe.net 43 response-auth-type: rsa-pubkey some-incredibly-long-public-key response-auth-type: none remarks: you can request rsa signature on queries submit-address: mailto://auto-dbm@ripe.net submit-address: rps-query://whois.ripe.net:43 submit-auth-type: pgp-key crypt-pw mail-from remarks: these are the authentication types supported mnt-by: maint-ripe-db refresh: 3600 expire: 14400 remarks: refresh and expire same as in DNS SOA ... remarks: admin and technical contact, etc source: IANA In each repository there should be a special repository object named ROOT. This should point to the root repository or to a higher level repository. This is to allow queries to be directed to the local repository but refer to the full set of registries for resolution of hierarchically allocated objects. The ``repository'' object and its usage is described in greater detail in Section 9. 8.1 Maintainer Objects The maintainer objects serve as a container to hold authentication filters. The authentication methods are described in Section 7. The maintainer can be referenced by name in other objects, most notably in the mnt-by attributes of those objects. Villamizar, et. al. Expires November 15, 1998 [Page 11] INTERNET-DRAFT Routing Policy System Security May 15, 1998 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 (usually 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 interpreted as the absence of any control over changes. This is highly inadvisable and most repositories will no longer allow this. The ``mnt-routes'' attribute are needed to reference maintainer objects to provide specific permissions related to the object. This is an extensions to RPSL and RIPE-181 proposed in this document and are described in detail in Section 9. 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 exact 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. 8.2 The 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 specific AS, address or route space by allowing modify and delete privileges regardless of the mnt-by in the object itself. The reclaim and no-reclaim attributes contain contain lists of objects subject to the reclaim and no-reclaim. See Section 9 for a full description of the reclaim and no-reclaim attributes. 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 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 addition of the reclaim attribute does not remove autonomy of existing Villamizar, et. al. Expires November 15, 1998 [Page 12] INTERNET-DRAFT Routing Policy System Security May 15, 1998 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 be 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 no-reclaim attribute cannot be deleted unless there are no overlapped objects for which the submitter is not listed in the maintainer pointed to be the mnt-by of the overlapped object. 8.3 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 a problem now but would be if a more distributed routing repository is used. The ``as-block'' object also makes it possible to separate AS number allocation from registration of AS routing policy. as-block: AS1321 - AS1335 delegated: ANS ... The ``aut-num'' describes the routing policy for an AS and is critical for router configuration of that AS and for analysis performed by another AS. For the purpose of this document it is sufficient to consider the aut-num solely as a place holder identifying the existence of an AS and providing a means to associate authorization with that AS for the purpose of 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. Villamizar, et. al. Expires November 15, 1998 [Page 13] INTERNET-DRAFT Routing Policy System Security May 15, 1998 8.4 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 subdelegations 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 delegated: RIPE ... source: IANA This inetnum simply delegates the storage of any more specific inetnum objects overlapping the stated range to the RIPE repository. An exact match of this inetnum may exist in the RIPE repository to provide hooks for the attributes referencing maintainer objects. The ``inetnum'' exists to support address allocation. For external number registries, such as those using ``[r]whoisd[++]'' the ``inetnum'' 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 corresponding routing registry. 8.5 route objects Currently there are a quite few route objects in more than one registry. 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. With the previous authorization restrictions, this could result in a route object for the same prefix in more than one database. The example below is a route registered differently in two databases (and registered incorrectly). This would now require a delegation attribute. route: 128.32.0.0/16 delegated: MCI RADB Villamizar, et. al. Expires November 15, 1998 [Page 14] INTERNET-DRAFT Routing Policy System Security May 15, 1998 The ``delegated'' attribute should be single valued for all objects except those that are granfathered due to addition prior to the use of these authorization rules. This is to prevent race conditions involving mutually exclusive additions with the same origin AS in different repositories. 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 contain incidents of erroneous route announcements (Section 5) and to support network problem diagnosis. 8.6 Other Objects Many of the RPSL ancillary objects have no natural hierarchy the way AS numbers, Internet addresses and routes have a numeric hierarchy. Some examples are ``maintainers'', ``people'' and ``role'' objects. For these objects, lack of any hierarchy leads to two problems. 1. There is no hierarchy that can be exploited to direct queries to alternate registries. At some point the query strategy of searching 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 local database and to use explicit references to an external repository where needed. A possible syntax is to precede the object key with the name of the repository and a delimiter. For example, the delimiter ``::'' can be used to form the NIC handle ``RIPE::CO19''. Currently there is a desire to keep NIC handles unique so the naming 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 ref- erence ``IANA::CO19''. There is no possibility of accidentally forget- ting to adhere to the conventions when making an addition and the exist- ing 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 Villamizar, et. al. Expires November 15, 1998 [Page 15] INTERNET-DRAFT Routing Policy System Security May 15, 1998 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 do- main 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 listing a larger set of employees but listing the more restrictive maintainer 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. 8.7 Query Processing A query may have to span multiple repositories. All queries should be directed toward a local repository which may mirror the root repository 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, inetnum, and route, the search begins at the root database and follows the hierarchy. For objects types that have no natural hierarchy, such as maintainers, people, and roles, 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. Otherwise the default is generally the local database or a default set by the repository. The default can be specified in the query itself. In searching for an AS, the AS blocks can be consulted, moving the search to data from other repositories. Eventually 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 can be determined and assignment determined if it is assigned. The search for a route is similar except the search may branch to more than one repository. The most specific route in one repository 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 Villamizar, et. al. Expires November 15, 1998 [Page 16] INTERNET-DRAFT Routing Policy System Security May 15, 1998 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. 8.8 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 maintainers. The referral-by and referral-in attribute can be set to refer to itself in this special case (Section 9 describes the referral-by and referral-in). 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 initially populated with the allocation of an inetnum covering the prefix 0/0, indicating that some address allocation authority exists. Similarly 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 8.7. 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 exist, 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 inetnum blocks is followed until the most specific is found. The submission 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 8.9). If the aut-num does not exist on a route add, then the addition is rejected (see Section A 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 will return one or more route objects. The submission must match an Villamizar, et. al. Expires November 15, 1998 [Page 17] INTERNET-DRAFT Routing Policy System Security May 15, 1998 applicable maintainer in at least one of these route objects for the ad- dition 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 unallo- cated 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 authorization 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 attribute, then any more specific objects of the same type must be examined. 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 reclaim 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. 8.9 Modifying or Deleting Database Objects When modifying or deleting any existing object a search for the object is performed as described in Section 8.7. If the submission matches an applicable maintainer for the object, then the operation can proceed. An applicable maintainer for a modification is any maintainer referenced by the mnt-by attribute in the object. For route and inetnum 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 A 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 existing inetnums that are more specific. The same check of the reclaim attribute that is made during addition must be made when a reclaim attribute is added by a modification (see Section 8.8). Villamizar, et. al. Expires November 15, 1998 [Page 18] INTERNET-DRAFT Routing Policy System Security May 15, 1998 A deletion is considered a special case of the modify operation. The deleted object may remain in the database with a ``deleted'' attribute in which case the mnt-by can still be consulted to remove the ``deleted'' attribute. 9 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 certain 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. 9.1 Changes to the RIPE/RPSL Schema Two object types are added to the RIPE/RPSL schema. A few attributes are added to existing object types. There are significant changes to the rules which determine if the addition of an object is authorized. Additional keywords representing new authentication types are added to the semantics of the existing ``auth'' attribute. The new object types are listed below. The first attribute listed is the key attribute and also serves as the name of the object type. repository key mandatory single unique query-address mandatory multiple Villamizar, et. al. Expires November 15, 1998 [Page 19] INTERNET-DRAFT Routing Policy System Security May 15, 1998 response-auth-type mandatory multiple submit-address mandatory multiple submit-auth-type mandatory multiple refresh optional single expire mandatory single descr optional multiple remarks optional multiple admin-c mandatory multiple tech-c mandatory multiple notify optional multiple mnt-by mandatory multiple changed mandatory multiple source mandatory single as-block key mandatory single unique delegated optional single descr optional multiple 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 types only a small number of the attribute types are new. These are: repository This attribute provides the name of the repository. This is the key field for the object and is single and must be globally unique. This is the same name used in the source attribute of all objects in that repository. query-address This attribute provides a host name and a port number used to direct queries. Optional fields may follow the port number at a later time and should be ignored. Alternately a URL format may be used. The special protocol identified ``rps-query'' can be used in URL format. response-auth-type This attribute provides the authentication types that may be used by the repository when responding to queries. submit-address This attribute provides a host name and a port number used to submit objects to the repository. Optional fields may follow the port number at a later time and should be ignored. Alternately a URL format may be used. The special protocol identified ``rps-query'' can be used in URL format. submit-auth-type This attribute provides the authentication types that may be used by the repository when responding to queries. Villamizar, et. al. Expires November 15, 1998 [Page 20] INTERNET-DRAFT Routing Policy System Security May 15, 1998 refresh Near real time flooding of repository updates is recommended as a method of distributing database changes. The refresh suggests a time interval for processing updates. Time is in seconds if expressed as an integer. Alternately, the letters ``h'', ``m'', or ``s'' can be used to indicate hours, minutes, and seconds. expire If near real time flooding is temporarily not operational, objects should be considered non-authoritative after this interval, and cannot be used for authorization purposes. as-block This attribute provides the AS number range for an ``as-block'' object. delegated This attribute indicates that further searches for object in the hierarchy must be made in one or more alternate repositories. The current repository may be listed. 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 identifying a PGP identity whose public key is held in an external keyring. The use of this method is depricated in favor of the ``pgp-key'' method. pgp-key The remainder of the attribute provides a PGP public key block in ASCII radix-64 format. 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 implementations 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, inetnum, or route object. This attribute references a maintainer object which is used in determining authorization for the addition of inetnum and route objects. If a mnt-routes object is absent, the mnt-by attribute is used for this purpose. The mnt-routes attribute is optional and multiple. the format is identical the Villamizar, et. al. Expires November 15, 1998 [Page 21] INTERNET-DRAFT Routing Policy System Security May 15, 1998 the exiting ``mnt-by'' but has an additional optional range preceeding the authorization information. The syntax for the range is the word ``range'' followed by a prefix lists (as defined in RPSL) in curly braces (``{\and \}") asused elsewherein RPSL. reclaim Thereclaim attributemay appearinas-block, aut-num,inetnum, orroute objects. Any objectof thesame typebelow inthe hierarchymay bemodified ordeleted bythe maintainerof theobject containinga reclaimattribute. Thevalue of theattribute isa setor rangeof objects ofthe sametype wherethe syntaxof theset orrange isas definedin RPSL. SeeSection 8.2for restrictionson addingreclaim attributes. no-reclaim Theno-reclaim attribute is usedwith the reclaimattribute. Theno-reclaim at- tributenegates any reclaimattribute it overlaps. See Section8.2 for restrictions ondeleting no-reclaimattributes. delegated Thedelegated attributeisallowed inany objecttype withahierarchy. This attribute indicatesthatfurther searchesfor objectin thehierarchy mustbe madein oneor morealternate repositories.The currentrepository maybe listed. referral-by Thisattribute isrequired inthe maintainer object.It maynever be alteredafter theaddition ofthe maintainer. Thisattribute refers tothe maintainerthat created thismain- tainer.It maybe multiple ifmore thanone signatureappeared onthe transaction creatingthe object. referral-in Thisattribute mayappear in amaintainer object. Itis multiple. Eachtime the maintainerobjectis usedto addanother maintainer,a referral-inreferencingthe newmaintainer isautomatically added. auth-override Anauth-override attributecan beadded, deleted,or changedby a transaction submittedby maintainerlisted inthereferal-by. The auth-overrideattribute itselfcontains only thedate whenthe attributewill gointo effect whichmust beat least60 days fromthe current dateunless thereis alreadyauthorization tomodify themaintainer. Afterthe date inthe auth- overrideis reached, thoseidentified by themaintainer in thereferal-by have authorization to modifythe maintainer. This attribute existsas a means toclean up should theholder of a maintainerbecomeunresponsive andcan onlytake effectif thatmaintainer doesnot removethe auth-overridein responseto theautomatic notificationthat occurson changes. Each repository must identify itself with a ``repository'' object. The repository must also contain a special ``repository'' whose key 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'' object type. The ``mnt-by'' attribute is now mandatory in all object types. Villamizar, et. al. Expires November 15, 1998 [Page 22] INTERNET-DRAFT Routing Policy System Security May 15, 1998 A new maintainer may be added by any existing maintainer. The ``referral-by'' attribute is now mandatory in the ``maintainer'' object 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. In order to add a maintainer to another database, a ``referral-in'' attribute is needed, containing the name of the external database. A ``referral- in'' attribute cannot be deleted unless there are no ``referral-by'' references to the maintainer in the named external databases. A 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 authorization 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. A.1 Relaxing requirements for ease of registry If the requirement that an aut-num exists is relaxed, then it is possible 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 willing to field requests to add inetnum records for the party already allocated the address space. Villamizar, et. al. Expires November 15, 1998 [Page 23] INTERNET-DRAFT Routing Policy System Security May 15, 1998 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 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 contain 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 main- tainer. Currently only the registry themselves may add maintainers. This becomes 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 maintainers that have a ``referral-by'' attribute can add maintainers. The ``referral-by'' and ``referral-in'' cannot be modified. This require- ment 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 maintainers 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 covering the space that registry allocates and essentially requiring null allo- cation (for example a ``crypt-pw'' authentication where the password is given in the remarks in the object or its maintainer) or those ob- taining addresses from that number authority will have trouble regis- tering in the routing registry. The authorization model supports either option, though it would be preferable if the number authorities cooper- ated 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. Villamizar, et. al. Expires November 15, 1998 [Page 24] INTERNET-DRAFT Routing Policy System Security May 15, 1998 A.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 allo- cations of address space. The routing registry would be wise to stay as neutral as possible with regard to disputes between third parties. The ``reclaim'' and ``no-reclaim'' are designed to allow either out- come to the decision as to whether the holder of a less specific inet- num or route object can exercise control over suballocations in the registry. The routing registry itself must decide whether to retain 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 dispute only af- ter the dispute has been resolved in court and a court order has been is- sued. 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 outside 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 distributed 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 overriding normal authorization to change the registry contents if a reclaim is not present. A.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 Villamizar, et. al. Expires November 15, 1998 [Page 25] INTERNET-DRAFT Routing Policy System Security May 15, 1998 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 obsoleted 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 requirements. 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 existing 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 maintainer 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 im- mediately or added later if needed. Villamizar, et. al. Expires November 15, 1998 [Page 26] INTERNET-DRAFT Routing Policy System Security May 15, 1998 B Common Operational Cases In principle address allocation and route allocation should be hierarchical with the hierarchy corresponding to the physical topology. In practice this is often not the case for numerous reasons. The primary 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 multihomed 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 numeric hierarchy [20]. It is also acknowledged that renumbering IPv4 networks can be difficult [20, 3, 21]. 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. B.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 authorization 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 objects for their AS, or the party allocated the address space can Villamizar, et. al. Expires November 15, 1998 [Page 27] INTERNET-DRAFT Routing Policy System Security May 15, 1998 give 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. B.2 aggregation and multihomed more specific routes Aggregation is normally not a problem if a provider is aggregating address 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 aggregation 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 allocation 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 an inetnum or by signing the submission along with the other parties. A more common case is where a more specific route object must be registered with a different AS than the aggregate due to the prefix being multihomed. In this case, the maintainer of the aggregate can create a more specific route object with their own AS marked withdrawn so as not to be routable. The new AS can be included in the maintainer solely for the purpose of allowing them to create a new route object with their own AS. Again, alternately both parties can sign the submission for the addition with the new AS. B.3 provider independent addresses and multiple origin AS Provider independent addresses and multihoming arrangement using multiple origin AS present a similar problem to multihoming. The maintainer of the address space and the maintainer of the AS is not the same. Permission can be granted using additions to the maintainer or multiple signatures can appear on the submission. B.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 Villamizar, et. al. Expires November 15, 1998 [Page 28] INTERNET-DRAFT Routing Policy System Security May 15, 1998 the AS of the new provider rather than the AS of the multihomed customer. A provider may be hesitant to give permissions to their competitor to make additions with their AS. There is no potential for harm in giving permission to a withdrawn exact match of the more specific so the maintainer of the aggregate could more easily in effect grant permission to the maintainers of the new AS. B.5 renumbering grace periods Renumbering grace periods allow a provider who wants to keep an address allocation intact to allow a customer who has chosen to go to another provider to renumber their network gradually and then return 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 indefinite 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 8.1 provides a means to end the grace period. C Deployment Considerations This section describes deployment considerations. The intention is to raise issues and discuss approaches rather than to provide a deployment 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 5. 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 routing 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 connectivity problems are reported. The majority of providers register prefixes but do not implement strict prefix filtering. Deploying new authentication mechanisms has no adverse consequences. Villamizar, et. al. Expires November 15, 1998 [Page 29] INTERNET-DRAFT Routing Policy System Security May 15, 1998 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 number 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. 1. During the transition from the NSFNET PRDB to the RADB a large number of prefixes were registered with an origin AS corresponding 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 registry 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 accountability. 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 necessary cleanup. This issue is discussed in Section A. 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. Villamizar, et. al. Expires November 15, 1998 [Page 30] INTERNET-DRAFT Routing Policy System Security May 15, 1998 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''. 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 substantial 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 existence of address registration information, minimal cooperation of the currently separate address registries is required. The extent of the cooperation amounts to sending cryptographically signed transactions 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 authorizations are not yet implemented. Minimal schema changes have to be made to support the ability to delegate objects for which there is an authorization 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. Acknowledgments This document draws ideas from numerous discussions and contributions of the IETF Routing Policy System Work Group and RIPE Routing Work Group. Villamizar, et. al. Expires November 15, 1998 [Page 31] INTERNET-DRAFT Routing Policy System Security May 15, 1998 References [1] C. Alaettinoglu, T. Bates, E. Gerich, D. Karrenberg, D. Meyer, M. Terpstra, and C. Villamizar. Routing policy specification language (rpsl). Technical Report RFC 2280, Internet Engineering Task Force, 1998. ftp://ds.internic.net/rfc/rfc2280.txt. [2] T. Bates, E. Gerich, L. Joncheray, J-M. Jouanigot, D. Karrenberg, M. Terpstra, and J. Yu. Representation of ip routing policies in a routing reg- istry (ripe-81++). Technical Report RFC 1786, Internet Engineer- ing Task Force, 1995. ftp://ds.internic.net/rfc/rfc1786.txt. [3] H. Berkowitz. Router renumbering guide. Technical Report RFC 2072, Internet Engineer- ing Task Force, 1997. ftp://ds.internic.net/rfc/rfc2072.txt. [4] H.W. Braun. Models of policy based routing. Technical Report RFC 1104, Internet Engineering Task Force, 1989. ftp://ds.internic.net/rfc/rfc1104.txt. [5] H.W. Braun and Y. Rekhter. Advancing the nsfnet routing ar- chitecture. Technical Report RFC 1222, Internet Engineering Task Force, 1991. ftp://ds.internic.net/rfc/rfc1222.txt. [6] D.D. Clark. Policy routing in internet protocols. Technical Re- port RFC 1102, Internet Engineering Task Force, 1989. ftp://ds.internic.net/rfc/rfc1102.txt. [7] D. Crocker. Standard for the format of arpa internet text messages. Technical Report RFC 822, Internet Engi- neering Task Force, 1982. ftp://ds.internic.net/rfc/rfc822.txt. [8] V. Fuller, T. Li, J. Yu, and K. Varadhan. Classless inter-domain routing (cidr): an address assignment and aggregation strat- egy. Technical Report RFC 1519, Internet Engineering Task Force, 1993. ftp://ds.internic.net/rfc/rfc1519.txt. [9] Internet Engineering Steering Group and R. Hinden. Applicability statement for the implementation of classless inter-domain rout- ing (cidr). Technical Report RFC 1517, Internet Engineering Task Force, 1993. ftp://ds.internic.net/rfc/rfc1517.txt. [10] J. Hawkinson and T. Bates. Guidelines for creation, selection, and registration of an autonomous system (as). Technical Report RFC 1930, Internet Engineering Task Force, 1996. ftp://ds.internic.net/rfc/rfc1930.txt. [11] K. Hubbard, M. Kosters, D. Con- rad, D. Karrenberg, and J. Postel. Internet registry ip alloca- tion guidelines. Technical Report RFC 2050, Internet Engineering Task Force, 1996. ftp://ds.internic.net/rfc/rfc2050.txt. Villamizar, et. al. Expires November 15, 1998 [Page 32] INTERNET-DRAFT Routing Policy System Security May 15, 1998 [12] David Kessens and Carol Or- ange. Ripe-181 to rpsl transition plan. Internet Draft (Work in Progress) draft-ietf-rps-transition-02, Internet Engineering Task Force, 11 1997. ftp://ds.internic.net/internet- drafts/draft-ietf-rps-transition-02.txt. [13] Mark Knopper and Steven J. Richardson. Aggregation support in the nsfnet policy-based rout- ing database. Technical Report RFC 1482, Internet Engineering Task Force, 1993. ftp://ds.internic.net/rfc/rfc1482.txt. [14] David Meyer, Cengiz Alaettinoglu, and David Kessens. Guidelines for extending rpsl. Internet Draft (Work in Progress) draft-ietf-rps-extending-00, Internet Engineering Task Force, 11 1997. ftp://ds.internic.net/internet- drafts/draft-ietf-rps-extending-00.txt. [15] David Meyer, Cengiz Alaettinoglu, and J. Schmitz. Application of routing policy specification language (rpsl) on the internet. Internet Draft (Work in Progress) draft-ietf-rps-appl- rpsl-01, Internet Engineering Task Force, 7 1997. ftp://ds.internic.net/internet-drafts/draft-ietf-rps-appl- rpsl-01.txt. [16] National Institute of Standards and Technology. The digital sig- nature standard, proposal and discussion. Communications of the ACM, 35(7):36--54, July 1992. [17] National Institute of Standards and Technology (NIST). Fips pub- lication 186: Digital signature standard (dss). Technical re- port, Gaithersburg, MD, May 1994. [18] Y. Rekhter. Routing in a multi-provider internet. Technical Re- port RFC 1787, Internet Engineering Task Force, 1995. ftp://ds.internic.net/rfc/rfc1787.txt. [19] Y. Rekhter and T. Li. An architecture for ip address allocation with cidr. Technical Report RFC 1518, Internet Engineering Task Force, 1993. ftp://ds.internic.net/rfc/rfc1518.txt. [20] Y. Rekhter and T. Li. Implications of various address allocation policies for internet routing. Technical Report RFC 2008, Inter- net Engineering Task Force, 1996. ftp://ds.internic.net/rfc/rfc2008.txt. [21] Y. Rekhter, P. Lothberg, R. Hinden, S. Deer- ing, and J. Postel. An ipv6 provider-based unicast address for- mat. Technical Report RFC 2073, Internet Engineering Task Force, 1997. ftp://ds.internic.net/rfc/rfc2073.txt. [22] Bruce Schneier. Applied Cryptography. Wiley, New York, 1996. Villamizar, et. al. Expires November 15, 1998 [Page 33] INTERNET-DRAFT Routing Policy System Security May 15, 1998 Security Considerations @@ This entire document is about security but at some point we need to figure out what belongs here in this case. Maybe the Area Directors can provide some advice. Author's Addresses Curtis Villamizar ANS Communications Cengiz Alaettinoglu ISI David M. Meyer University of Oregon Sandy Murphy Trusted Information Systems Carol Orange RIPE NCC Villamizar, et. al. Expires November 15, 1998 [Page 34]