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Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The exact meaning of the all-uppercase expression 'MAY NOT' is not defined in RFC 2119. If it is intended as a requirements expression, it should be rewritten using one of the combinations defined in RFC 2119; otherwise it should not be all-uppercase. == The expression 'MAY NOT', while looking like RFC 2119 requirements text, is not defined in RFC 2119, and should not be used. Consider using 'MUST NOT' instead (if that is what you mean). Found 'MAY NOT' in this paragraph: When using a metric which is also influenced by other local policy, an 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 MAY NOT upgrade an Invalid announcement to Valid or better. -- The document date (July 10, 2011) is 4667 days in the past. Is this intentional? Checking references for intended status: Best Current Practice ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Downref: Normative reference to an Informational draft: draft-ietf-sidr-arch (ref. 'I-D.ietf-sidr-arch') == Outdated reference: A later version (-16) exists of draft-ietf-sidr-ghostbusters-04 == Outdated reference: A later version (-08) exists of draft-ietf-sidr-ltamgmt-02 == Outdated reference: A later version (-10) exists of draft-ietf-sidr-pfx-validate-01 == Outdated reference: A later version (-09) exists of draft-ietf-sidr-repos-struct-08 == Outdated reference: A later version (-26) exists of draft-ietf-sidr-rpki-rtr-13 ** Downref: Normative reference to an Informational RFC: RFC 5781 Summary: 2 errors (**), 0 flaws (~~), 8 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group R. Bush 3 Internet-Draft Internet Initiative Japan 4 Intended status: BCP July 10, 2011 5 Expires: January 11, 2012 7 RPKI-Based Origin Validation Operation 8 draft-ietf-sidr-origin-ops-10 10 Abstract 12 Deployment of RPKI-based BGP origin validation has many operational 13 considerations. This document attempts to collect and present them. 14 It is expected to evolve as RPKI-based origin validation is deployed 15 and the dynamics are better understood. 17 Requirements Language 19 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 20 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 21 document are to be interpreted as described in RFC 2119 [RFC2119]. 23 Status of this Memo 25 This Internet-Draft is submitted in full conformance with the 26 provisions of BCP 78 and BCP 79. 28 Internet-Drafts are working documents of the Internet Engineering 29 Task Force (IETF). Note that other groups may also distribute 30 working documents as Internet-Drafts. The list of current Internet- 31 Drafts is at http://datatracker.ietf.org/drafts/current/. 33 Internet-Drafts are draft documents valid for a maximum of six months 34 and may be updated, replaced, or obsoleted by other documents at any 35 time. It is inappropriate to use Internet-Drafts as reference 36 material or to cite them other than as "work in progress." 38 This Internet-Draft will expire on January 11, 2012. 40 Copyright Notice 42 Copyright (c) 2011 IETF Trust and the persons identified as the 43 document authors. All rights reserved. 45 This document is subject to BCP 78 and the IETF Trust's Legal 46 Provisions Relating to IETF Documents 47 (http://trustee.ietf.org/license-info) in effect on the date of 48 publication of this document. Please review these documents 49 carefully, as they describe your rights and restrictions with respect 50 to this document. Code Components extracted from this document must 51 include Simplified BSD License text as described in Section 4.e of 52 the Trust Legal Provisions and are provided without warranty as 53 described in the Simplified BSD License. 55 Table of Contents 57 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 58 2. Suggested Reading . . . . . . . . . . . . . . . . . . . . . . . 3 59 3. RPKI Distribution and Maintenance . . . . . . . . . . . . . . . 3 60 4. Within a Network . . . . . . . . . . . . . . . . . . . . . . . 5 61 5. Routing Policy . . . . . . . . . . . . . . . . . . . . . . . . 5 62 6. Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 63 7. Security Considerations . . . . . . . . . . . . . . . . . . . . 7 64 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7 65 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 7 66 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 67 10.1. Normative References . . . . . . . . . . . . . . . . . . . 7 68 10.2. Informative References . . . . . . . . . . . . . . . . . . 8 69 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 9 71 1. Introduction 73 RPKI-based origin validation relies on widespread deployment of the 74 Resource Public Key Infrastructure (RPKI) [I-D.ietf-sidr-arch]. How 75 the RPKI is distributed and maintained globally is a serious concern 76 from many aspects. 78 The global RPKI is in very initial stages of deployment, there is no 79 single root trust anchor, initial testing is being done by the IANA 80 and the RIRs, and there is a technical testbed. It is thought that 81 origin validation based on the RPKI will be deployed incrementally 82 over the next year to five years. 84 Origin validation needs to be done only by an AS's border routers and 85 is designed so that it can be used to protect announcements which are 86 originated by large providers, upstreams and down-streams, and by 87 small stub/enterprise/edge routers. 89 Origin validation has been designed to be deployed on current routers 90 without significant hardware upgrade. It should be used in border 91 routers by operators from large backbones to small stub/entetprise/ 92 edge networks. 94 RPKI-based origin validation has been designed so that, with prudent 95 local routing policies, there is little risk that what is seen as 96 today's normal Internet routing is threatened by imprudent deployment 97 of the global RPKI, see Section 5. 99 2. Suggested Reading 101 It is assumed that the reader understands BGP, [RFC4271], the RPKI, 102 see [I-D.ietf-sidr-arch], the RPKI Repository Structure, see 103 [I-D.ietf-sidr-repos-struct], ROAs, see [I-D.ietf-sidr-roa-format], 104 the RPKI to Router Protocol, see [I-D.ietf-sidr-rpki-rtr], RPKI-based 105 Prefix Validation, see [I-D.ietf-sidr-pfx-validate], and Ghostbusters 106 Records, see [I-D.ietf-sidr-ghostbusters]. 108 3. RPKI Distribution and Maintenance 110 The RPKI is a distributed database containing certificates, CRLs, 111 manifests, ROAs, and Ghostbusters Records as described in 112 [I-D.ietf-sidr-repos-struct]. Policies and considerations for RPKI 113 object generation and maintenance are discussed elsewhere. 115 A local valid cache containing all RPKI data may be gathered from the 116 global distributed database using the rsync protocol, [RFC5781], and 117 a validation tool such as rcynic [rcynic]. 119 Validated caches may also be created and maintained from other 120 validated caches. Network operators SHOULD take maximum advantage of 121 this feature to minimize load on the global distributed RPKI 122 database. Of course, the recipient SHOULD re-validate the data. 124 As RPKI-based origin validation relies on the availability of RPKI 125 data, operators SHOULD locate caches close to routers that require 126 these data and services. A router can peer with one or more nearby 127 caches. 129 For redundancy, a router SHOULD peer with more than one cache at the 130 same time. Peering with two or more, at least one local and others 131 remote, is recommended. 133 If an operator trusts upstreams to carry their traffic, they MAY also 134 trust the RPKI data those upstreams cache, and SHOULD peer with those 135 caches. Note that this places an obligation on those upstreams to 136 maintain fresh and reliable caches. And, as usual, the recipient 137 SHOULD re-validate the data. 139 A transit provider or a network with peers SHOULD validate origins in 140 announcements made by upstreams, down-streams, and peers. They still 141 SHOULD trust the caches provided by their upstreams. 143 Before issuing a ROA for a super-block, an operator MUST ensure that 144 any sub-allocations from that block which are announced by other ASs, 145 e.g. customers, have correct ROAs in the RPKI. Otherwise, issuing a 146 ROA for the super-block will cause the announcements of sub- 147 allocations with no ROAs to be viewed as Invalid, see 148 [I-D.ietf-sidr-pfx-validate]. 150 Use of RPKI-based origin validation removes any need to originate 151 more specifics to protect against mis-origination of a less specific 152 prefix. Having a ROA for the covering prefix should protect it. 154 To aid translation of ROAs into efficient search algorithms in 155 routers, ROAs SHOULD be as precise as possible, i.e. match prefixes 156 as announced in BGP. E.g. software and operators SHOULD avoid use of 157 excessive max length values in ROAs unless operationally necessary. 159 One advantage of minimal ROA length is that the forged origin attack 160 does not work for sub-prefixes that are not covered by overly long 161 max length. E.g. if, instead of 10.0.0.0/16-24, one issues 162 10.0.0.0/16 and 10.0.42.0/24, a forged origin attack can not succeed 163 against 10.0.66.0/24. They must attack the whole /16, which is more 164 likely to be noticed. 166 Therefore, ROA generation software MUST use the prefix length as the 167 max length if the user does not specify a max length. 169 Operators SHOULD be conservative in use of max length in ROAs. E.g., 170 if a prefix will have only a few sub-prefixes announced, multiple 171 ROAs for the specific announcements SHOULD be used as opposed to one 172 ROA with a long max length. 174 An environment where private address space is announced in eBGP the 175 operator MAY have private RPKI objects which cover these private 176 spaces. This will require a trust anchor created and owned by that 177 environment, see [I-D.ietf-sidr-ltamgmt]. 179 Operators issuing ROAs may have customers which announce their own 180 prefixes and ASs into global eBGP but who do not wish to go though 181 the work to manage the relevant certificates and ROAs. Operators 182 SHOULD offer to provision the RPKI data for these customers just as 183 they provision many other things for them. 185 While a an operator using RPKI data MAY choose any polling frequency 186 they wish for ensuring they have a fresh RPKI cache. However, if 187 they use RPKI data as an input to operational routing decisions, they 188 SHOULD ensure local cache freshness at least every four to six hours. 190 4. Within a Network 192 Origin validation need only be done by edge routers in a network, 193 those which border other networks/ASs. 195 A validating router will use the result of origin validation to 196 influence local policy within its network, see Section 5. In 197 deployment this policy should fit into the AS's existing policy, 198 preferences, etc. This allows a network to incrementally deploy 199 validation-capable border routers. 201 eBGP speakers which face more critical peers or up/down-streams are 202 candidates for the earliest deployment. Validating more critical 203 received announcements should be considered in partial deployment. 205 5. Routing Policy 207 Origin validation based on the RPKI marks a received announcement as 208 having an origin which is Valid, NotFound, or Invalid. See 209 [I-D.ietf-sidr-pfx-validate]. How this is used in routing SHOULD be 210 specified by the operator's local policy. 212 Local policy using relative preference is suggested to manage the 213 uncertainty associated with a system in early deployment, applying 214 local policy to eliminate the threat of unroutability of prefixes due 215 to ill-advised certification policies and/or incorrect certification 216 data. E.g. until the community feels comfortable relying on RPKI 217 data, routing on Invalid origin validity, though at a low preference, 218 MAY occur. 220 As origin validation will be rolled out incrementally, coverage will 221 be incomplete for a long time. Therefore, routing on NotFound 222 validity state SHOULD be done for a long time. As the transition 223 moves forward, the number of BGP announcements with validation state 224 NotFound should decrease. Hence an operator's policy SHOULD NOT be 225 overly strict, preferring Valid announcements, attaching a lower 226 preference to, but still using, NotFound announcements, and dropping 227 or giving very low preference to Invalid announcements. 229 Some may choose to use the large Local-Preference hammer. Others 230 might choose to let AS-Path rule and set their internal metric, which 231 comes after AS-Path in the BGP decision process. 233 When using a metric which is also influenced by other local policy, 234 an operator should be careful not to create privilege upgrade 235 vulnerabilities. E.g. if Local Pref is set depending on validity 236 state, be careful that peer community signaling MAY NOT upgrade an 237 Invalid announcement to Valid or better. 239 Announcements with Valid origins SHOULD be preferred over those with 240 NotFound or Invalid origins, if the latter are accepted at all. 242 Announcements with NotFound origins SHOULD be preferred over those 243 with Invalid origins. 245 Announcements with Invalid origins MAY be used, but SHOULD be less 246 preferred than those with Valid or NotFound. 248 6. Notes 250 Like the DNS, the global RPKI presents only a loosely consistent 251 view, depending on timing, updating, fetching, etc. Thus, one cache 252 or router may have different data about a particular prefix than 253 another cache or router. There is no 'fix' for this, it is the 254 nature of distributed data with distributed caches. 256 There is some uncertainty about the origin AS of aggregates and what, 257 if any, ROA can be used. The long range solution to this is the 258 deprecation of AS-SETs, see [I-D.wkumari-deprecate-as-sets]. 260 Operators who manage certificates SHOULD associate RPKI Ghostbusters 261 Records (see [I-D.ietf-sidr-ghostbusters]) with each publication 262 point they control. These are publication points holding the CRL, 263 ROAs, and other signed objects issued by the operator, and made 264 available to other ASs in support of routing on the public Internet. 266 7. Security Considerations 268 As the BGP origin AS of an update is not signed, origin validation is 269 open to malicious spoofing. Therefore, RPKI-based origin validation 270 is designed to deal only with inadvertent mis-advertisement. 272 Origin validation does not address the problem of AS-Path validation. 273 Therefore paths are open to manipulation, either malicious or 274 accidental. 276 As BGP does not ensure that traffic will flow via the paths it 277 advertises, the data plane may not follow the control plane. 279 Be aware of the class of privilege escalation issues discussed in 280 Section 5 above. 282 8. IANA Considerations 284 This document has no IANA Considerations. 286 9. Acknowledgments 288 The author wishes to thank Rob Austein, Steve Bellovin, Steve Kent, 289 Pradosh Mohapatra, Chris Morrow, Sandy Murphy, Keyur Patel, Heather 290 and Jason Schiller, John Scudder, Kotikalapudi Sriram, Maureen 291 Stillman, and Dave Ward. 293 10. References 295 10.1. Normative References 297 [I-D.ietf-sidr-arch] 298 Lepinski, M. and S. Kent, "An Infrastructure to Support 299 Secure Internet Routing", draft-ietf-sidr-arch-13 (work in 300 progress), May 2011. 302 [I-D.ietf-sidr-ghostbusters] 303 Bush, R., "The RPKI Ghostbusters Record", 304 draft-ietf-sidr-ghostbusters-04 (work in progress), 305 June 2011. 307 [I-D.ietf-sidr-ltamgmt] 308 Reynolds, M. and S. Kent, "Local Trust Anchor Management 309 for the Resource Public Key Infrastructure", 310 draft-ietf-sidr-ltamgmt-02 (work in progress), June 2011. 312 [I-D.ietf-sidr-pfx-validate] 313 Mohapatra, P., Scudder, J., Ward, D., Bush, R., and R. 314 Austein, "BGP Prefix Origin Validation", 315 draft-ietf-sidr-pfx-validate-01 (work in progress), 316 February 2011. 318 [I-D.ietf-sidr-repos-struct] 319 Huston, G., Loomans, R., and G. Michaelson, "A Profile for 320 Resource Certificate Repository Structure", 321 draft-ietf-sidr-repos-struct-08 (work in progress), 322 June 2011. 324 [I-D.ietf-sidr-roa-format] 325 Lepinski, M., Kent, S., and D. Kong, "A Profile for Route 326 Origin Authorizations (ROAs)", 327 draft-ietf-sidr-roa-format-12 (work in progress), 328 May 2011. 330 [I-D.ietf-sidr-rpki-rtr] 331 Bush, R. and R. Austein, "The RPKI/Router Protocol", 332 draft-ietf-sidr-rpki-rtr-13 (work in progress), June 2011. 334 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 335 Requirement Levels", BCP 14, RFC 2119, March 1997. 337 [RFC5781] Weiler, S., Ward, D., and R. Housley, "The rsync URI 338 Scheme", RFC 5781, February 2010. 340 10.2. Informative References 342 [I-D.wkumari-deprecate-as-sets] 343 Kumari, W., "Deprecation of BGP AS_SET, AS_CONFED_SET.", 344 draft-wkumari-deprecate-as-sets-01 (work in progress), 345 September 2010. 347 [RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway 348 Protocol 4 (BGP-4)", RFC 4271, January 2006. 350 [rcynic] "rcynic read-me", 351 . 353 Author's Address 355 Randy Bush 356 Internet Initiative Japan 357 5147 Crystal Springs 358 Bainbridge Island, Washington 98110 359 US 361 Phone: +1 206 780 0431 x1 362 Email: randy@psg.com