--- 1/draft-ietf-sidr-bgpsec-ops-01.txt 2012-03-08 09:13:58.730754054 +0100 +++ 2/draft-ietf-sidr-bgpsec-ops-02.txt 2012-03-08 09:13:58.746807924 +0100 @@ -1,252 +1,178 @@ Network Working Group R. Bush Internet-Draft Internet Initiative Japan -Intended status: BCP October 19, 2011 -Expires: April 21, 2012 +Intended status: BCP March 8, 2012 +Expires: September 9, 2012 BGPsec Operational Considerations - draft-ietf-sidr-bgpsec-ops-01 + draft-ietf-sidr-bgpsec-ops-02 Abstract Deployment of the BGPsec architecture and protocols has many operational considerations. This document attempts to collect and present them. It is expected to evolve as BGPsec is formalized and initially deployed. 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]. + document are to be interpreted as described in [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 April 21, 2012. + This Internet-Draft will expire on September 9, 2012. Copyright Notice - Copyright (c) 2011 IETF Trust and the persons identified as the + Copyright (c) 2012 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 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. AS/Router Certificates . . . . . . . . . . . . . . . . . . . . 4 + 4. AS/Router Certificates . . . . . . . . . . . . . . . . . . . . 3 5. Within a Network . . . . . . . . . . . . . . . . . . . . . . . 4 - 6. Considerations for Edge Sites . . . . . . . . . . . . . . . . . 5 - 7. Beaconing Considerations . . . . . . . . . . . . . . . . . . . 5 - 8. Routing Policy . . . . . . . . . . . . . . . . . . . . . . . . 6 - 9. Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 - 10. Security Considerations . . . . . . . . . . . . . . . . . . . . 8 - 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8 - 12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 8 - 13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8 - 13.1. Normative References . . . . . . . . . . . . . . . . . . . 8 - 13.2. Informative References . . . . . . . . . . . . . . . . . . 8 - Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 9 + 6. Considerations for Edge Sites . . . . . . . . . . . . . . . . . 4 + 7. Routing Policy . . . . . . . . . . . . . . . . . . . . . . . . 5 + 8. Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 + 9. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 + 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7 + 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 + 11.1. Normative References . . . . . . . . . . . . . . . . . . . 7 + 11.2. Informative References . . . . . . . . . . . . . . . . . . 7 + Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 8 1. Introduction BGPsec is a new protocol with many operational considerations. It is expected to be deployed incrementally over a number of years. As - core BGPsec-capable routers may require large memory and crypto - assist, it is thought that origin validation based on the RPKI will - occur over the next two to five years and that BGPsec will start to + core BGPsec-capable routers may require large memory and/or modern + CPUs, it is thought that origin validation based on the RPKI will + occur over the next one to three years and that BGPsec will start to deploy late in that window. BGPsec relies on widespread propagation of the Resource Public Key - Infrastructure (RPKI) [I-D.ietf-sidr-arch]. How the RPKI is - distributed and maintained globally and within an operator's - infrastructure may be different for BGPsec than for origin - validation. + Infrastructure (RPKI) [RFC6480]. How the RPKI is distributed and + maintained globally and within an operator's infrastructure may be + different for BGPsec than for origin validation. - BGPsec need be spoken only by a AS's eBGP speaking, AKA border, + BGPsec need be spoken only by an AS's eBGP speaking, AKA border, routers, and is designed so that it can be used to protect - announcements which are originated by small edge routers, and this - has special operational considerations. + announcements which are originated by small edge routers. This has + special operational considerations. Different prefixes have different timing and replay protection considerations. 2. Suggested Reading It is assumed that the reader understands BGP, [RFC4271], BGPsec, - [I-D.lepinski-bgpsec-overview], the RPKI, see [I-D.ietf-sidr-arch], - the RPKI Repository Structure, see [I-D.ietf-sidr-repos-struct], and - ROAs, see [I-D.ietf-sidr-roa-format]. + [I-D.lepinski-bgpsec-overview], the RPKI, see [RFC6480], the RPKI + Repository Structure, see [RFC6481], and ROAs, see [RFC6482]. 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. - - 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, at least one local and others - remote, is recommended. - - If an operator trusts upstreams to carry their traffic, they SHOULD - also trust the RPKI data those upstreams cache, and SHOULD 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 SHOULD validate NLRI in - announcements made by upstreams, downstreams, and peers. To minimize - impact on the global RPKI, they SHOULD fetch from and then revalidate - data from caches provided by their upstreams. - - 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, see [I-D.ietf-sidr-ltamgmt]. + All non-ROA considerations in the section on RPKI Distribution and + Maintenance of [I-D.ietf-sidr-pfx-validate] apply. 4. AS/Router Certificates + As described in [I-D.ymbk-bgpsec-rtr-rekeying] routers MAY be capable + of generating their own public/private key-pairs and having their + certificates signed and published in the RPKI by the RPKI CA system, + and/or MAY be given public/private key-pairs by the operator. + A site/operator MAY use a single certificate/key in all their routers, one certificate/key per router, or any granularity in between. A large operator, concerned that a compromise of one router's key - would make many routers vulnerable, MAY accept a more complex + would make other routers vulnerable, MAY accept a more complex certificate/key distribution burden to reduce this exposure. On the other extreme, an edge site with one or two routers MAY use a single certificate/key. - Routers MAY be capable of generating their own keys and having their - certificates signed and published in the RPKI by their NOC. This - would mean that a router's private key need never leave the router. - 5. Within a Network BGPsec is spoken by edge routers in a network, those which border other networks/ASs. In a fully BGPsec enabled AS, Route Reflectors MUST have BGPsec - enabled if and only if there are eBGP speakers in their client cone. + enabled if and only if there are eBGP speakers in their client cone + (the transitive closure of their customers' customers' customers' + ...). A BGPsec capable router MAY use the data it receives to influence - local policy within its network, see Section 8. In deployment this + local policy within its network, see Section 7. In deployment this policy should fit into the AS's existing policy, preferences, etc. This allows a network to incrementally deploy BGPsec capable border routers. eBGP speakers which face more critical peers or up/downstreams would be candidates for the earliest deployment. Both securing one's own announcements and validating received announcements should be considered in partial deployment. - An eBGP listener MUST NOT trust non-BGPsec markings such as - communities received across a trust boundary. + As they are not signed, an eBGP listener SHOULD NOT strongly trust + unsigned markings such as communities received across a trust + boundary. 6. Considerations for Edge Sites An edge site which does not provide transit and trusts its upstream(s) SHOULD only originate a signed prefix announcement and need not validate received announcements. BGPsec protocol capability negotiation provides for a speaker signing the data it sends but being unable to accept signed data. Thus a smallish edge router may hold only its own signing key(s) and sign it's announcement but not receive signed announcements and therefore - not need to deal with the majority of the RPKI. + not need to deal with the majority of the RPKI. Thus such routers + CPU, RAM, and crypto needs are trivial and additional hardware should + not be needed. As the vast majority (84%) of ASs are stubs, and they announce the majority of prefixes, this allows for simpler and cheaper early incremental deployment. It may also mean that edge sites concerned with routing security will be attracted to upstreams which support BGPsec. -7. Beaconing Considerations - - The BGPsec protocol attempts to reduce exposure to replay attacks by - allowing the route originator to sign an announcement with a validity - period and re-announce well within that period. - - This re-announcement is termed 'beaconing'. All timing values are, - of course, jittered. - - It is only the originator of an NLRI which signs the announcement - with a validity period. - - To reduce vulnerability to a lost beacon announcement, a router - SHOULD beacon at a rate somewhat greater than half the signature - validity period it uses. - - As beaconing places a load on the entire global routing system, - careful thought MUST be given to any need to beacon frequently. This - would be based on a conservative estimation of the vulnerability to a - replay attack. - - Beacon timing and signature validity periods SHOULD be as follows: - - The Exemplary Citizen: Prefix originators who are not overly - concerned about replay attacks might announce with a signature - validity of multiple weeks and beacon one third of the validity - period. - - Normal Prefix: Most prefixes SHOULD announce with a signature - validity of a week and beacon every three days. - - Critical Prefix: Of course, we all think what we do is critical. - But prefixes of top level DNS servers, and RPKI publication points - are actually critical to large swaths of the Internet and are - therefore tempting targets for replay attacks. It is suggested - that the beaconing of these prefixes SHOULD be two to four hours, - with a signature validity of six to twelve hours. - - Note that this may incur route flap damping (RFD) with current - default but deprecated RFD parameters, see [I-D.ymbk-rfd-usable]. - -8. Routing Policy +7. Routing Policy Unlike origin validation based on the RPKI, BGPsec marks a received announcement as Valid or Invalid, there is no NotFound state. How this is used in routing is up to the operator's local policy. See [I-D.ietf-sidr-pfx-validate]. As BGPsec will be rolled out over years and does not allow for intermediate non-signing edge routers, coverage will be spotty for a long time. Hence a normal operator's policy SHOULD NOT be overly strict, perhaps preferring valid announcements and giving very low @@ -256,139 +182,142 @@ Local policy on the eBGP edge MAY convey the validation state of a BGP signed path through normal local policy mechanisms, e.g. setting a BGP community, or modifying a metric value such as local-preference or MED. Some MAY choose to use the large Local-Pref hammer. Others MAY choose to let AS-Path rule and set their internal metric, which comes after AS-Path in the BGP decision process. Because of possible RPKI version skew, an AS Path which does not validate at router R0 might validate at R1. Therefore, signed paths - that are invalid and yet propagated SHOULD have their signatures kept - intact and should be signed if sent to external BGPsec speakers. + that are invalid and yet propagated (because they are chosen as best + path) SHOULD have their signatures kept intact and MUST be signed if + sent to external BGPsec speakers. This implies that updates which a speaker judges to be invalid MAY be propagated to iBGP peers. Therefore, unless local policy ensures otherwise, a signed path learned via iBGP MAY be invalid. If needed, the validation state SHOULD be signaled by normal local policy mechanisms such as communities or metrics. On the other hand, local policy on the eBGP edge might preclude iBGP or eBGP announcement of signed AS Paths which are invalid. - If a BGPsec speaker receives an unsigned path, it SHOULD perform - origin validation per [I-D.ietf-sidr-pfx-validate]. + A BGPsec speaker receiving a path SHOULD perform origin validation + per [I-D.ietf-sidr-pfx-validate]. If it is known that a BGPsec neighbor is not a transparent route server, and the router provides a knob to disallow a received pCount (prepend count, zero for transparent route servers) of zero, that - knob SHOULD be applied. + knob SHOULD be applied. Routers should default to this knob + disallowing pCount 0. -9. Notes + To prevent exposure of the internals of BGP Confederations [RFC5065], + a BGPsec speaker which is a Member-AS of a Confederation MUST NOT + sign updates sent to another Member-AS of the same Confederation. + +8. Notes + + For protection from attacks replaying BGP data on the order of a day + or longer old, re-keying routers with new keys (previously) + provisioned in the RPKI is sufficient. For one procedure, see + [I-D.rogaglia-sidr-bgpsec-rollover] 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. Operators who manage certificates SHOULD have RPKI Ghostbuster Records (see [I-D.ietf-sidr-ghostbusters]), signed indirectly by End Entity certificates, for those certificates on which others' routing depends for certificate and/or ROA validation. As a router must evaluate certificates and ROAs which are time dependent, routers' clocks MUST be correct to a tolerance of approximately an hour. - If a router has reason to believe its clock is seriouly incorrect, + If a router has reason to believe its clock is seriously incorrect, e.g. it has a time earlier than 2011, it SHOULD NOT attempt to validate incoming updates. It SHOULD defer validation until it believes it is within reasonable time tolerance. - Servers should provide time service, such as NTP [RFC5905], to client + Servers should provide time service, such as [RFC5905], to client routers. -10. Security Considerations +9. Security Considerations - BGPsec is all about security, routing security. The major security - considerations for the protocol are described in - [I-D.ietf-sidr-bgpsec-protocol]. + The major security considerations for the BGPsec protocol are + described in [I-D.ietf-sidr-bgpsec-protocol]. -11. IANA Considerations +10. IANA Considerations This document has no IANA Considerations. -12. Acknowledgments - - The author wishes to thank the BGPsec design team. - -13. References +11. References -13.1. Normative References +11.1. Normative References [I-D.ietf-sidr-bgpsec-protocol] Lepinski, M., "BGPSEC Protocol Specification", - draft-ietf-sidr-bgpsec-protocol-00 (work in progress), - June 2011. + draft-ietf-sidr-bgpsec-protocol-01 (work in progress), + October 2011. [I-D.ietf-sidr-ghostbusters] Bush, R., "The RPKI Ghostbusters Record", - draft-ietf-sidr-ghostbusters-15 (work in progress), - October 2011. + draft-ietf-sidr-ghostbusters-16 (work in progress), + December 2011. - [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-12 (work in progress), - May 2011. + [I-D.lepinski-bgpsec-overview] + Lepinski, M. and S. Turner, "An Overview of BGPSEC", + draft-lepinski-bgpsec-overview-00 (work in progress), + March 2011. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. -13.2. Informative References + [RFC6480] Lepinski, M. and S. Kent, "An Infrastructure to Support + Secure Internet Routing", RFC 6480, February 2012. - [I-D.ietf-sidr-arch] - Lepinski, M. and S. Kent, "An Infrastructure to Support - Secure Internet Routing", draft-ietf-sidr-arch-13 (work in - progress), May 2011. + [RFC6481] Huston, G., Loomans, R., and G. Michaelson, "A Profile for + Resource Certificate Repository Structure", RFC 6481, + February 2012. - [I-D.ietf-sidr-ltamgmt] - Reynolds, M. and S. Kent, "Local Trust Anchor Management - for the Resource Public Key Infrastructure", - draft-ietf-sidr-ltamgmt-02 (work in progress), June 2011. + [RFC6482] Lepinski, M., Kent, S., and D. Kong, "A Profile for Route + Origin Authorizations (ROAs)", RFC 6482, February 2012. + +11.2. Informative References [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-02 (work in progress), - July 2011. - - [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-09 (work in progress), - July 2011. + draft-ietf-sidr-pfx-validate-03 (work in progress), + October 2011. - [I-D.lepinski-bgpsec-overview] - Lepinski, M. and S. Turner, "An Overview of BGPSEC", - draft-lepinski-bgpsec-overview-00 (work in progress), - March 2011. + [I-D.rogaglia-sidr-bgpsec-rollover] + Gagliano, R., Patel, K., and B. Weis, "BGPSEC router key + roll-over as an alternative to beaconing", + draft-rogaglia-sidr-bgpsec-rollover-00 (work in progress), + March 2012. - [I-D.ymbk-rfd-usable] - Pelsser, C., Bush, R., Patel, K., Mohapatra, P., and O. - Maennel, "Making Route Flap Damping Usable", - draft-ymbk-rfd-usable-01 (work in progress), June 2011. + [I-D.ymbk-bgpsec-rtr-rekeying] + Turner, S., Patel, K., and R. Bush, "Router Keying for + BGPsec", draft-ymbk-bgpsec-rtr-rekeying-00 (work in + progress), March 2012. [RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway Protocol 4 (BGP-4)", RFC 4271, January 2006. + [RFC5065] Traina, P., McPherson, D., and J. Scudder, "Autonomous + System Confederations for BGP", RFC 5065, August 2007. + [RFC5905] Mills, D., Martin, J., Burbank, J., and W. Kasch, "Network Time Protocol Version 4: Protocol and Algorithms Specification", RFC 5905, June 2010. Author's Address Randy Bush Internet Initiative Japan 5147 Crystal Springs Bainbridge Island, Washington 98110