Network Working Group R. Bush Internet-Draft IIJ Intended status: BCP February 1, 2011 Expires: August 5, 2011 RPKI-Based Origin Validation Operation draft-ietf-sidr-origin-ops-05 Abstract Deployment of the RPKI-based BGP origin validation has many operational considerations. This document attempts to collect and present them. It is expected to evolve as RPKI-based origin validation is deployed and the dynamics are better understood. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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." This Internet-Draft will expire on August 5, 2011. Copyright Notice Copyright (c) 2011 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents Bush Expires August 5, 2011 [Page 1] Internet-Draft RPKI-Based Origin Validation Operation February 2011 carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Suggested Reading . . . . . . . . . . . . . . . . . . . . . . . 3 3. RPKI Distribution and Maintenance . . . . . . . . . . . . . . . 3 4. Within a Network . . . . . . . . . . . . . . . . . . . . . . . 4 5. Routing Policy . . . . . . . . . . . . . . . . . . . . . . . . 5 6. Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 7. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 6 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 10.1. Normative References . . . . . . . . . . . . . . . . . . . 7 10.2. Informative References . . . . . . . . . . . . . . . . . . 7 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 7 Bush Expires August 5, 2011 [Page 2] Internet-Draft RPKI-Based Origin Validation Operation February 2011 1. Introduction RPKI-based origin validation relies on widespread propagation of the Resource Public Key Infrastructure (RPKI) [I-D.ietf-sidr-arch]. How the RPKI is distributed and maintained globally is a serious concern from many aspects. The global RPKI has yet to be deployed, only a testbed exists, and some beta testing is being done by the IANA and some RIRs. It is expected to be deployed incrementally over a number of years. It is thought that origin validation based on the RPKI will deploy over the next year to five years. Origin validation only need be done by an AS's border routers and is designed so that it can be used to protect announcements which are originated by large providers, upstreams and downstreams, and by small stub/enterprise/edge routers. Origin validation has been designed to be deployed on current routers without hardware upgrade. It should be used by everyone from large backbones to small stub/entetprise/edge routers. RPKI-based origin validation has been designed so that, with prudent local routing policies, there is little risk that normal Internet routing is threatened by imprudent deployment of the global RPKI, see Section 5. 2. Suggested Reading It is assumed that the reader understands BGP, [RFC4271], the RPKI, see [I-D.ietf-sidr-arch], the RPKI Repository Structure, see [I-D.ietf-sidr-repos-struct], ROAs, see [I-D.ietf-sidr-roa-format], the RPKI to Router Protocol, see [I-D.ietf-sidr-rpki-rtr], and RPKI- based Prefix Validation, see [I-D.ietf-sidr-pfx-validate]. 3. RPKI Distribution and Maintenance The RPKI is a distributed database containing certificates, CRLs, manifests, ROAs, and Ghostbuster Records as described in [I-D.ietf-sidr-repos-struct]. Policies and considerations for RPKI object generation and maintenance are discussed elsewhere. A local valid cache containing all RPKI data may be gathered from the global distributed database using the rsync protocol and a validation tool such as rcynic. Bush Expires August 5, 2011 [Page 3] Internet-Draft RPKI-Based Origin Validation Operation February 2011 Validated caches may also be created and maintained from other validated caches. Network operators SHOULD take maximum advantage of this feature to minimize load on the global distributed RPKI database. As RPKI-based origin validation relies on the availability of RPKI data, operators SHOULD locate caches close to routers that require these data and services. A router can peer with one or more nearby caches. For redundancy, a router SHOULD peer with more than one cache at the same time. Peering with two or more, one local and others remote, is recommended. If an operator trusts upstreams to carry their traffic, they can also trust the RPKI data those upstreams cache, and peer with those caches. Note that this places an obligation on those upstreams to maintain fresh and reliable caches. A transit provider or a network with peers will want to validate origins in announcements made by downstreams and peers. They still SHOULD trust the caches provided by their upstreams. Before issuing a ROA for a block, an operator MUST ensure that any sub-allocations from that block which are announced by others (e.g. customers) have ROAs in play. Otherwise, issuing a ROA for the super-block will cause the announcements of sub-allocations with no ROAs to be Invalid. An environment where private address space is announced in eBGP the operator MAY have private RPKI objects which cover these private spaces. This will require a trust anchor created and owned by that environment. "Operators issuing ROAs may have customers announce into global eBGP but do not wish to go though the work to manage their own certificates and ROAs. The operator SHOULD provision the RPKI data for these customers just as they provision many other things for them. 4. Within a Network Origin validation need only be done by edge routers in a network, those which border other networks/ASs. A validating router will use the result of origin validation to influence local policy within its network, see Section 5. In Bush Expires August 5, 2011 [Page 4] Internet-Draft RPKI-Based Origin Validation Operation February 2011 deployment this policy should fit into the AS's existing policy, preferences, etc. This allows a network to incrementally deploy validation capable border routers. eBGP speakers which face more critical peers or up/downstreams would be candidates for the earliest deployment. Validating more critical received announcements should be considered in partial deployment. 5. Routing Policy Origin validation based on the RPKI merely marks a received announcement as having an origin which is Valid, NotFound, or Invalid. See [I-D.ietf-sidr-pfx-validate]. How this is used in routing is specified by the operator's local policy. Local policy using relative preference is suggested to manage the uncertainty associated with a system in flux, applying local policy to eliminate the threat of unroutability of prefixes due to ill- advised certification policies and/or incorrect certification data. E.g. until the community feels comfortable relying on RPKI data, routing on Invalid origin validity, though at a low preference, may be common. As origin validation will be rolled out incrementally, coverage will be incomplete for a long time. Therefore, routing on NotFound validity state will be advisable for a long time. As the transition moves forward, the number of BGP announcements with validation state NotFound should decrease. Hence an operator's policy SHOULD NOT be overly strict, preferring Valid announcements, attaching a lower preference to, but still using, NotFound announcements, and dropping or giving very low preference to Invalid announcements. Some may choose to use the large Local-Preference hammer. Others might choose to let AS-Path rule and set their internal metric, which comes after AS-Path in the BGP decision process. When using a metric which is also influenced by other local policy, the operator should be careful not to create privilege upgrade vulnerabilities. E.g. if Local Pref is set depending on validity state, be careful that peer community signaling can not upgrade an invalid announcement to valid or better. Announcements with Valid origins SHOULD be preferred over those with NotFound or Invalid origins. Announcements with NotFound origins SHOULD be preferred over those with Invalid origins. Bush Expires August 5, 2011 [Page 5] Internet-Draft RPKI-Based Origin Validation Operation February 2011 Announcements with Invalid origins MAY be used, but SHOULD be less preferred than those with Valid or NotFound. 6. Notes Like the DNS, the global RPKI presents only a loosely consistent view, depending on timing, updating, fetching, etc. Thus, one cache or router may have different data about a particular prefix than another cache or router. There is no 'fix' for this, it is the nature of distributed data with distributed caches. There is some uncertainty about the origin AS of aggregates and what, if any, ROA can be used. The long range solution to this is the deprecation of AS-SETs, see [I-D.wkumari-deprecate-as-sets]. 7. Security Considerations As the BGP origin is not signed, origin validation is open to malicious spoofing. It is only designed to deal with inadvertent mis-advertisement. Origin validation does not address the problem of AS-Path validation. Therefore paths are open to manipulation, either malicious or accidental. The data plane may not follow the control plane. Be aware of the class of privilege escalation issues discussed in Section 5 above. 8. IANA Considerations This document has no IANA Considerations. 9. Acknowledgments The author wishes to thank Rob Austein, Steve Bellovin, Pradosh Mohapatra, Chris Morrow, Sandy Murphy, Keyur Patel, Heather and Jason Schiller, John Scudder, Maureen Stillman, and Dave Ward. 10. References Bush Expires August 5, 2011 [Page 6] Internet-Draft RPKI-Based Origin Validation Operation February 2011 10.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [I-D.ietf-sidr-arch] Lepinski, M. and S. Kent, "An Infrastructure to Support Secure Internet Routing", draft-ietf-sidr-arch-11 (work in progress), September 2010. [I-D.ietf-sidr-repos-struct] Huston, G., Loomans, R., and G. Michaelson, "A Profile for Resource Certificate Repository Structure", draft-ietf-sidr-repos-struct-06 (work in progress), November 2010. [I-D.ietf-sidr-roa-format] Lepinski, M., Kent, S., and D. Kong, "A Profile for Route Origin Authorizations (ROAs)", draft-ietf-sidr-roa-format-09 (work in progress), November 2010. [I-D.ietf-sidr-rpki-rtr] Bush, R. and R. Austein, "The RPKI/Router Protocol", draft-ietf-sidr-rpki-rtr-07 (work in progress), January 2011. [I-D.ietf-sidr-pfx-validate] Mohapatra, P., Scudder, J., Ward, D., Bush, R., and R. Austein, "BGP Prefix Origin Validation", draft-ietf-sidr-pfx-validate-00 (work in progress), July 2010. 10.2. Informative References [RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway Protocol 4 (BGP-4)", RFC 4271, January 2006. [I-D.wkumari-deprecate-as-sets] Kumari, W., "Deprecation of BGP AS_SET, AS_CONFED_SET.", draft-wkumari-deprecate-as-sets-01 (work in progress), September 2010. Bush Expires August 5, 2011 [Page 7] Internet-Draft RPKI-Based Origin Validation Operation February 2011 Author's Address Randy Bush Internet Initiative Japan, Inc. 5147 Crystal Springs Bainbridge Island, Washington 98110 US Phone: +1 206 780 0431 x1 Email: randy@psg.com Bush Expires August 5, 2011 [Page 8]