One document matched: draft-ietf-opsec-bgp-security-02.xml
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docName="draft-ietf-opsec-bgp-security-02.txt" >
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<front>
<title abbrev="BGP OPSEC">BGP operations and security</title>
<author
fullname="Jerome Durand"
initials="J."
surname="Durand">
<organization abbrev="CISCO Systems, Inc.">CISCO Systems, Inc.</organization>
<address>
<postal>
<street>11 rue Camille Desmoulins</street>
<code>92782 CEDEX</code>
<city>Issy-les-Moulineaux</city>
<country>FR</country>
</postal>
<email>jerduran@cisco.com</email>
</address>
</author>
<author
fullname="Ivan Pepelnjak"
initials="I."
surname="Pepelnjak">
<organization abbrev="NIL">NIL Data Communications</organization>
<address>
<postal>
<street>Tivolska 48</street>
<code>1000</code>
<city>Ljubljana</city>
<country>Slovenia</country>
</postal>
<email>ip@ipspace.net</email>
</address>
</author>
<author
fullname="Gert Doering"
initials="G."
surname="Doering">
<organization abbrev="SpaceNet">SpaceNet AG</organization>
<address>
<postal>
<street>Joseph-Dollinger-Bogen 14</street>
<code>D-80807</code>
<city>Muenchen</city>
<country>Germany</country>
</postal>
<email>gert@space.net</email>
</address>
</author>
<date year="2014" month="January"/>
<area>Operations & Management</area>
<workgroup>Internet Engineering Task Force</workgroup>
<abstract>
<t>BGP (Border Gateway Protocol) is the protocol almost exclusively used in the Internet to exchange routing information between network domains. Due to this central nature, it is important to understand the security measures that can and should be deployed to prevent accidental or intentional routing disturbances.</t>
<t>This document describes measures to protect the BGP sessions itself (like TTL, MD5, control plane filtering) and to better control the flow of routing information, using prefix filtering and automatization of prefix filters, max-prefix filtering, AS path filtering, route flap dampening and BGP community scrubbing.</t>
</abstract>
<note title="Foreword">
<t>A placeholder to list general observations about this document.</t>
</note>
<note title="Requirements Language">
<t>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 <xref target="RFC2119">RFC 2119</xref>.
</t>
</note>
</front>
<middle>
<section anchor="Intro" title="Introduction">
<t><xref target="RFC4271">BGP</xref> is the protocol used in the internet to exchange routing information between network domains. This protocol does not directly include mechanisms that control that routes exchanged conform to the various rules defined by the Internet community. This document intends to both summarize common existing rules and help network administrators apply coherent BGP policies.</t>
</section>
<section anchor="Definition" title="Definitions and Accronyms">
<t><list style="symbols">
<t>ACL: Access Control List</t>
<t>IRR: Internet Routing Registry</t>
<t>IXP: Internet eXchange Point</t>
<t>LIR: Local Internet Registry</t>
<t>pMTUd: Path MTU Discovery</t>
<t>RIR: regional Internet Registry</t>
<t>Tier 1 transit provider: an IP transit provider which can reach any network on the internet without purchasing transit services</t>
<t>uRPF: Unicast Reverse Path Forwarding</t>
</list>
</t>
</section>
<section anchor="RouterProtection" title="Protection of the BGP router">
<t>The BGP router needs to be protected from stray packets. This protection should be achieved by an access control list (ACL) which would discard all packets directed to TCP port 179 on the local device and sourced from an address not known or permitted to become a BGP neighbor. If supported, an ACL specific to the control-plane of the router should be used (receive-ACL, control-plane policing, etc.), to avoid configuration of data-plane filters for packets transiting through the router (and therefore not reaching the control plane). If the hardware can not do that, interface ACLs can be used to block packets to the local router.</t>
<t>Some routers automatically program such an ACL upon BGP configuration. On other devices this ACL should be configured and maintained manually or using scripts.</t>
<t>The filtering of packets destined to the local router is a wider topic than "just for BGP" (if you bring down a router by overloading one of the other protocols from remote, BGP is harmed as well). For a more detailed recommendation, see <xref target="RFC6192">RFC6192</xref>.</t>
</section>
<section anchor="SessionProtection" title="Protection of BGP sessions">
<t>Current issues of TCP-based protocols (therefore including BGP) have been documented in <xref target="RFC6952" />. The following sub-sections recall the major points raised in this RFC and gives best practices for BGP operation.</t>
<section anchor="SessionProtectionMD5" title="Protection of TCP sessions used by BGP">
<t>Attacks on TCP sessions used by BGP (ex: sending spoofed TCP RST packets) could bring down the TCP session. Following a successful ARP spoofing attack (or other similar Man-in-the-Middle attack), the attacker might even be able to inject packets into the TCP stream (routing attacks).</t>
<t>TCP sessions used by BGP can be secured with a variety of mechanisms. MD5 protection of TCP session header <xref target="RFC2385" /> is the most common one as it was the first mechanism widely implemented on routers. IPsec or TCP Authentication Option (TCP-AO, <xref target="RFC5925" />) offer stronger protection and should now be preferred when available.</t>
<t>The drawback of TCP session protection is additional configuration and management overhead for authentication information (ex: MD5 password) maintenance. Protection of TCP sessions used by BGP is thus recommended when peerings are established over shared networks where spoofing can be done (like IXPs).</t>
<t>You SHOULD block spoofed packets (packets with a source IP address belonging to your IP address space) at all edges of your network, making the protection of TCP sessions used by BGP unnecessary on iBGP or eBGP sessions run over point-to-point links.</t>
</section>
<section anchor="SessionProtectionTTL" title="BGP TTL security (GTSM)">
<t>BGP sessions can be made harder to spoof with the Generalized TTL Security Mechanisms (aka TTL security) <xref target="RFC5082" />. Instead of sending TCP packets with TTL value = 1, the routers send the TCP packets with TTL value = 255 and the receiver checks that the TTL value equals 255. Since it's impossible to send an IP packet with TTL = 255 to a non-directly-connected IP host, BGP TTL security effectively prevents all spoofing attacks coming from third parties not directly connected to the same subnet as the BGP-speaking routers. Network administrators SHOULD implement TTL security on directly connected BGP peerings.</t>
<t>Note: Like MD5 protection, TTL security has to be configured on both ends of a BGP session.</t>
</section>
</section>
<section anchor="PrefixFiltering" title="Prefix filtering">
<t>The main aspect of securing BGP resides in controlling the prefixes that are received/advertised on the BGP peerings. Prefixes exchanged between BGP peers are controlled with inbound and outbound filters that can match on IP prefixes (prefix filters, <xref target="PrefixFiltering" />), AS paths (as-path filters, <xref target="ASpathFilters" />) or any other attributes of a BGP prefix (for example, BGP communities, <xref target="CommunityFilters" />).</t>
<section anchor="PrefixFilteringDefinition" title="Definition of prefix filters">
<t>This section list the most commonly used prefix filters. Following sections will clarify where these filters should be applied.</t>
<section anchor="PrefixFilteringNoRoute" title="Special purpose prefixes">
<section anchor="PrefixFilteringNoRouteIPv4" title="IPv4 special purpose prefixes">
<t>IPv4 registry <xref target="IANAipv4SpecialPurposeRegistry" /> maintains the list of IPv4 special purpose prefixes and their routing scope. Reader will refer to this registry in order to configure prefix filters. Only prefixes with value "False" in column "Global" MUST be discarded on Internet BGP peerings.</t>
</section>
<section anchor="PrefixFilteringNoRouteIPv6" title="IPv6 special purpose prefixes">
<t>IPv6 registry <xref target="IANAipv6SpecialPurposeRegistry" /> maintains the list of IPv6 special purpose prefixes and their routing scope. Reader will refer to this registry in order to configure prefix filters. Only prefixes with value "False" in column "Global" MUST be discarded on Internet BGP peerings.</t>
<t>At the time of the writing of this document, the list of IPv6 prefixes that MUST not cross network boundaries can be simplified as IANA allocates at the time being prefixes to RIR's only in 2000::/3 prefix <xref target="IANAipv6AddressSpace" />. All other prefixes (ULA's, link-local, multicast… are outside of that prefix) and therefore the simplified list becomes:
<list style="symbols">
<t>2001:DB8::/32 and more specifics - documentation <xref target="RFC3849" /></t>
<t>Prefixes more specifics than 2002::/16 - 6to4 <xref target="RFC3056" /></t>
<t>3FFE::/16 and more specifics - was initially used for the 6Bone (worldwide IPv6 test network) and returned to IANA</t>
<t>All prefixes that are outside 2000::/3 prefix</t>
</list></t>
</section>
</section>
<section anchor="PrefixFilteringNotAllocated" title="Prefixes not allocated">
<t>IANA allocates prefixes to RIRs which in turn allocate prefixes to LIRs. It is wise not to accept in the routing table prefixes that are not allocated. This could mean allocation made by IANA and/or allocations done by RIRs. This section details the options for building a list of allocated prefixes at every level. It is important to understand that filtering prefixes not allocated requires constant updates as prefixes are continually allocated. Therefore automation of such prefix filters is key for the success of this approach. One SHOULD probably NOT consider solutions described in this section if they are not capable of maintaining updated prefix filters: the damage would probably be worse than the intended security policy.</t>
<section anchor="PrefixFilteringNotAllocatedIANA" title="IANA allocated prefix filters">
<t>IANA has allocated all the IPv4 available space. Therefore there is no reason why one would keep checking prefixes are in the <xref target="IANAipv4AllocatedPrefixes">IANA allocated IPv4 address space</xref>. No specific filters need to be put in place by administrators who want to make sure that IPv4 prefixes they receive in BGP updates have been allocated by IANA.</t>
<t>For IPv6, given the size of the address space, it can be seen as wise accepting only prefixes derived from those allocated by IANA. Administrators can dynamically build this list from the <xref target="IANAipv6AllocatedPrefixes">IANA allocated IPv6 space</xref>. As IANA keeps allocating prefixes to RIRs, the aforementioned list should be checked regularly against changes and if they occur, prefix filters should be computed and pushed on network devices. The list could also be pulled directly by routers when they implement such mechanisms. As there is delay between the time a RIR receives a new prefix and the moment it starts allocating portions of it to its LIRs, there is no need doing this step quickly and frequently. Based on past experience, authors recommend that the process in place makes sure there is no more than one month between the time the IANA IPv6 allocated prefix list changes and the moment all IPv6 prefix filters are updated.</t>
<t>If process in place (manual or automatic) cannot guarantee that the list is updated regularly then it's better not to configure any filters based on allocated networks. The IPv4 experience has shown that many network operators implemented filters for prefixes not allocated by IANA but did not update them on a regular basis. This created problems for latest allocations and required a extra work for RIRs that had to "de-bogonize" the newly allocated prefixes.</t>
</section>
<section anchor="PrefixFilteringNotAllocatedRIR" title="RIR allocated prefix filters">
<t>A more precise check can be performed as one would like to make sure that prefixes they receive are being originated or transited by autonomous systems entitled to do so. It has been observed in the past that one could easily advertise someone else's prefix (or more specific prefixes) and create black holes or security threats. To partially mitigate this risk, administrators would need to make sure BGP advertisements correspond to information located in the existing registries. At this stage 2 options can be considered (short and long term options). They are described in the following subsections.</t>
</section>
<section anchor="PrefixFilteringNotAllocatedIRR" title="Prefix filters creation from Internet Routing Registries (IRR)">
<t>An Internet Routing Registry (IRR) is a database containing internet routing information, described using Routing Policy Specification Language objects <xref target="RFC4012" />. Network administrators are given privileges to describe routing policies of their own networks in the IRR and information is published, usually publicly. A majority of Regional Internet Registries do also operate an IRR and can control that registered routes conform to prefixes allocated or directly assigned.</t>
<t>It is possible to use the IRR information to build, for a given neighbor autonomous system, a list of prefixes originated or transited which one may accept. This can be done relatively easily using scripts and existing tools capable of retrieving this information in the registries. This approach is exactly the same for both IPv4 and IPv6.</t>
<t>The macro-algorithm for the script is described as follows. For the peer that is considered, the distant network administrator has provided the autonomous system and may be able to provide an AS-SET object (aka AS-MACRO). An AS-SET is an object which contains AS numbers or other AS-SETs. An operator may create an AS-SET defining all the AS numbers of its customers. A tier 1 transit provider might create an AS-SET describing the AS-SET of connected operators, which in turn describe the AS numbers of their customers. Using recursion, it is possible to retrieve from an AS-SET the complete list of AS numbers that the peer is likely to announce. For each of these AS numbers, it is also easy to check in the corresponding IRR for all associated prefixes. With these two mechanisms a script can build for a given peer the list of allowed prefixes and the AS number from which they should be originated. One could decide not use the origin information and only build monolithic prefix filters from fetched data.</t>
<t>As prefixes, AS numbers and AS-SETs may not all be under the same RIR authority, a difficulty resides choosing for each object the appropriate IRR to poll. Some IRRs have been created and are not restricted to a given region or authoritative RIR. They allow RIRs to publish information contained in their IRR in a common place. They also make it possible for any subscriber (probably under contract) to publish information too. When doing requests inside such an IRR, it is possible to specify the source of information in order to have the most reliable data. One could check a popular IRR containing many sources (such as <xref target="RADB">RADB</xref>, the Routing Assets Database) and only select as sources some desired RIRs and trusted major ISPs.</t>
<t>As objects in IRRs may frequently vary over time, it is important that prefix filters computed using this mechanism are refreshed regularly. A daily basis could even be considered as some routing changes must be done sometimes in a certain emergency and registries may be updated at the very last moment. It has to be noted that this approach significantly increases the complexity of the router configurations as it can quickly add tens of thousands configuration lines for some important peers.</t>
<t>Last but not least, authors recommend that network administrators publish and maintain their resources properly in IRR database maintained by their RIR, when available.</t>
</section>
<section anchor="PrefixFilteringNotAllocatedRIRsidr" title="SIDR - Secure Inter Domain Routing">
<t>An infrastructure called SIDR (Secure Inter-Domain Routing) <xref target="RFC6480" /> has been designed to secure internet advertisements. At the time this document is written, many documents have been published and a framework with a complete set of protocols is proposed so that advertisements can be checked against signed routing objects in RIR routing registries. There are basically two services that SIDR offers:
<list style="symbols">
<t>Origin validation <xref target="RFC6811" /> seeks at making sure that attributes associated with a routes are correct (the major point being the validation of the AS number originating this route). Origin validation is now operational (Internet registries, protocols, implementations on some routers...) and in theory it can be implemented knowing that the proportion of signed resources is still low at the time this document is written.</t>
<t>Path validation provided by BGPsec <xref target="BGPsec-req" /> seeks at making sure that no ones announce fake/wrong BGP paths that would attract trafic for a given destination <xref target="BGPsec-threat" />. BGPsec is still an on-going work item at the time this document is written and therefore cannot be implemented.</t>
</list></t>
<t>Implementing SIDR mechanisms is expected to solve many of BGP routing security problems in the long term but it may take time for deployments to be made and objects to become signed. It also has to be pointed that SIDR infrastructure is complementing (not replacing) the security best practices listed in this document. Authors therefore recommend to implement any SIDR proposed mechanism (example: route origin validation) on top of the other existing mechanisms even if they could sometimes appear targeting the same goal.</t>
<t>If route origin validation is implemented, authors recommend to refer to rules described in <xref target="RPKI-origin" />. In short, each external route received on a router SHOULD be checked against the RPKI data set:
<list style="symbols">
<t>If a corresponding ROA is found and is valid then the prefix SHOULD be accepted.</t>
<t>It the ROA is found and is INVALID then the prefix SHOULD be discarded.</t>
<t>If an ROA is not found then the prefix SHOULD be accepted but corresponding route SHOULD be given a low preference.</t>
</list></t>
<t>Authors also recommend that network operators sign their routing objects so their routes can be validated by other networks running origin validation.</t>
</section>
</section>
<section anchor="PrefixFilteringTooSpecific" title="Prefixes too specific">
<t>Most ISPs will not accept advertisements beyond a certain level of specificity (and in return do not announce prefixes they consider as too specific). That acceptable specificity is decided for each peering between the 2 BGP peers. Some ISP communities have tried to document acceptable specificity. This document does not make any judgement on what the best approach is, it just recalls that there are existing practices on the internet and recommends the reader to refer to what those are. As an example the RIPE community has documented that IPv4 prefixes longer than /24 and IPv6 prefixes longer than /48 are generally not announced/accepted in the internet <xref target="RIPE-399" /> <xref target="RIPE-532" />.</t>
</section>
<section anchor="PrefixFilteringSelfPrefixes" title="Filtering prefixes belonging to the local AS and downstreams">
<t>A network SHOULD filter its own prefixes on peerings with all its peers (inbound direction). This prevents local traffic (from a local source to a local destination) from leaking over an external peering in case someone else is announcing the prefix over the Internet. This also protects the infrastructure which may directly suffer in case backbone's prefix is suddenly preferred over the Internet.</t>
<t>To an extent, such filters can also be configured on a network for the prefixes of its downstreams in order to protect them too. Such filters must be defined with caution as they can break existing redundancy mechanisms. For example in case an operator has a multihomed customer, it should keep accepting the customer prefix from its peers and upstreams. This will make it possible for the customer to keep accessing its operator network (and other customers) via the internet in case the BGP peering between the customer and the operator is down.</t>
</section>
<section anchor="PrefixFilteringExchangePoint" title="IXP LAN prefixes">
<section anchor="PrefixFilteringExchangePointNetworkSecurity" title="Network security">
<t>When a network is present on an IXP and peers with other IXP members over a common subnet (IXP LAN prefix), it MUST NOT accept more specific prefixes for the IXP LAN prefix from any of its external BGP peers. Accepting these routes may create a black hole for connectivity to the IXP LAN.</t>
<t>If the IXP LAN prefix is accepted as an "exact match", care needs to be taken to avoid other routers in the network sending IXP traffic towards the externally-learned IXP LAN prefix (recursive route lookup pointing into the wrong direction). This can be achieved by preferring IGP routes before eBGP, or by using "BGP next-hop-self" on all routes learned on that IXP.</t>
<t>If the IXP LAN prefix is accepted at all, it MUST only be accepted from the ASes that the IXP authorizes to announce it - which will usually be automatically achieved by filtering announcements by IRR DB.</t>
</section>
<section anchor="PrefixFilteringExchangePointPMTUD" title="pMTUd and the loose uRPF problem">
<t>In order to have pMTUd working in the presence of loose uRPF, it is necessary that all the networks that may source traffic that could flow through the IXP (ie. IXP members and their downstreams) have a route for the IXP LAN prefix. This is necessary as "packet too big" ICMP messages sent by IXP members' routers may be sourced using an address of the IXP LAN prefix. In the presence of loose uRPF, this ICMP packet is dropped if there is no route for the IXP LAN prefix or a less specific route covering IXP LAN prefix.</t>
<t>In that case, any IXP member SHOULD make sure it has a route for the IXP LAN prefix or a less specific prefix on all its routers and that it announces the IXP LAN prefix or less specific (up to a default route) to its downstreams. The announcements done for this purpose SHOULD pass IRR-generated filters described in <xref target="PrefixFilteringNotAllocatedIRR" /> as well as "prefixes too specific" filters described in <xref target="PrefixFilteringTooSpecific" />. The easiest way to implement this is that the IXP itself takes care of the origination of its prefix and advertises it to all IXP members through a BGP peering. Most likely the BGP route servers would be used for this. The IXP would most likely send its entire prefix which would be equal or less specific than the IXP LAN prefix.</t>
</section>
<section anchor="PrefixFilteringExchangePointExample" title="Example">
<t>Let's take as an example an IXP in the RIPE region for IPv4. It would be allocated a /22 by RIPE NCC (X.Y.0.0/22 in our example) and use a /23 of this /22 for the IXP LAN (let say X.Y.0.0/23). This IXP LAN prefix is the one used by IXP members to configure eBGP peerings. The IXP could also be allocated an AS number (AS64496 in our example).</t>
<t>Any IXP member MUST make sure it filters prefixes more specific than X.Y.0.0/23 from all its eBGP peers. If it received X.Y.0.0/24 or X.Y.1.0/24 this could seriously impact its routing.</t>
<t>The IXP SHOULD originate X.Y.0.0/22 and advertise it to its members through an eBGP peering (most likely from its BGP route servers, configured with AS64496).</t>
<t>The IXP members SHOULD accept the IXP prefix only if it passes the IRR generated filters (see <xref target="PrefixFilteringNotAllocatedIRR" />)</t>
<t>IXP members SHOULD then advertise X.Y.0.0/22 prefix to their downstreams. This announce would pass IRR based filters as it is originated by the IXP.</t>
</section>
</section>
<section anchor="PrefixFilteringDefault" title="The default route">
<section anchor="PrefixFilteringDefaultIPv4" title="IPv4">
<t>The 0.0.0.0/0 prefix is likely not intended to be accepted nor advertised other than in specific customer / provider configurations, general filtering outside of these is RECOMMENDED.</t>
</section>
<section anchor="PrefixFilteringDefaultIPv6" title="IPv6">
<t>The ::/0 prefix is likely not intended to be accepted nor advertised other than in specific customer / provider configurations, general filtering outside of these is RECOMMENDED.</t>
</section>
</section>
</section>
<section anchor="PrefixFilteringFullRouting" title="Prefix filtering recommendations in full routing networks">
<t>For networks that have the full internet BGP table, some policies should be applied on each BGP peer for received and advertised routes. It is recommended that each autonomous system configures rules for advertised and received routes at all its borders as this will protect the network and its peer even in case of misconfiguration. The most commonly used filtering policy is proposed in this section and uses prefix filters defined in previous section <xref target="PrefixFilteringDefinition" />.</t>
<section anchor="PrefixFilteringInternetPeers" title="Filters with internet peers">
<section anchor="PrefixFilteringInternetPeersInbound" title="Inbound filtering">
<t>There are basically 2 options, the loose one where no check will be done against RIR allocations and the strict one where it will be verified that announcements strictly conform to what is declared in routing registries.</t>
<section anchor="PrefixFilteringInternetPeersInboundLoose" title="Inbound filtering loose option">
<t>In this case, the following prefixes received from a BGP peer will be filtered:
<list style="symbols">
<t><xref target="PrefixFilteringNoRoute">Prefixes not globally routable</xref></t>
<t><xref target="PrefixFilteringNotAllocatedIANA">Prefixes not allocated by IANA (IPv6 only)</xref></t>
<t><xref target="PrefixFilteringTooSpecific">Routes too specific</xref></t>
<t><xref target="PrefixFilteringSelfPrefixes">Prefixes belonging to the local AS</xref></t>
<t><xref target="PrefixFilteringExchangePoint">IXP LAN prefixes</xref></t>
<t><xref target="PrefixFilteringDefault">The default route</xref></t>
</list></t>
</section>
<section anchor="PrefixFilteringInternetPeersInboundStrict" title="Inbound filtering strict option">
<t>In this case, filters are applied to make sure advertisements strictly conform to what is declared in routing registries (<xref target="PrefixFilteringNotAllocatedRIR" />). Warn is given as registries are not always accurate (prefixes missing, wrong information...) This varies accross the registries and regions of the Internet. Before applying a strict policy the reader SHOULD check the impact on the filter and make sure solution is not worse than the problem.</t>
<t>Also in case of script failure each administrator may decide if all routes are accepted or rejected depending on routing policy. While accepting the routes during that time frame could break the BGP routing security, rejecting them might re-route too much traffic on transit peers, and could cause more harm than what a loose policy would have done.</t>
<t>In addition to this, one could apply the following filters beforehand in case the routing registry used as source of information by the script is not fully trusted:
<list style="symbols">
<t><xref target="PrefixFilteringNoRoute">Prefixes not globally routable</xref></t>
<t><xref target="PrefixFilteringTooSpecific">Routes too specific</xref></t>
<t><xref target="PrefixFilteringSelfPrefixes">Prefixes belonging to the local AS</xref></t>
<t><xref target="PrefixFilteringExchangePoint">IXP LAN prefixes</xref></t>
<t><xref target="PrefixFilteringDefault">The default route</xref></t>
</list></t>
</section>
</section>
<section anchor="PrefixFilteringInternetPeersOutbound" title="Outbound filtering">
<t>Configuration should be put in place to make sure that only appropriate prefixes are sent. These can be, for example, prefixes belonging to both the network in question and its downstreams. This can be achieved by using a combination of BGP communities, AS-paths or both. It can also be desirable that following filters are positioned before to avoid unwanted route announcement due to bad configuration:
<list style="symbols">
<t><xref target="PrefixFilteringNoRoute">Prefixes not globally routable</xref></t>
<t><xref target="PrefixFilteringTooSpecific">Routes too specific</xref></t>
<t><xref target="PrefixFilteringExchangePoint">IXP LAN prefixes</xref></t>
<t><xref target="PrefixFilteringDefault">The default route</xref></t>
</list></t>
<t>In case it is possible to list the prefixes to be advertised, then just configuring the list of allowed prefixes and denying the rest is sufficient.</t>
</section>
</section>
<section anchor="PrefixFilteringCustomers" title="Filters with customers">
<section anchor="PrefixFilteringCustomersInbound" title="Inbound filtering">
<t>The inbound policy with end customers is pretty straightforward: only customers prefixes MUST be accepted, all others MUST be discarded. The list of accepted prefixes can be manually specified, after having verified that they are valid. This validation can be done with the appropriate IP address management authorities.</t>
<t>The same rules apply in case the customer is also a network connecting other customers (for example a tier 1 transit provider connecting service providers). An exception can be envisaged in case it is known that the customer network applies strict inbound/outbound prefix filtering, and the number of prefixes announced by that network is too large to list them in the router configuration. In that case filters as in <xref target="PrefixFilteringInternetPeersInbound" /> can be applied.</t>
</section>
<section anchor="PrefixFilteringCustomersOutbound" title="Outbound filtering">
<t>The outbound policy with customers may vary according to the routes customer wants to receive. In the simplest possible scenario, the customer may only want to receive only the default route, which can be done easily by applying a filter with the default route only.</t>
<t>In case the customer wants to receive the full routing (in case it is multihomed or if wants to have a view of the internet table), the following filters can be simply applied on the BGP peering:
<list style="symbols">
<t><xref target="PrefixFilteringNoRoute">Prefixes not globally routable</xref></t>
<t><xref target="PrefixFilteringTooSpecific">Routes too specific</xref></t>
<t><xref target="PrefixFilteringDefault">The default route</xref></t>
</list></t>
<t>There can be a difference for the default route that can be announced to the customer in addition to the full BGP table. This can be done simply by removing the filter for the default route. As the default route may not be present in the routing table, one may decide to originate it only for peerings where it has to be advertised.</t>
</section>
</section>
<section anchor="PrefixFilteringUpstreams" title="Filters with upstream providers">
<section anchor="PrefixFilteringUpstreamsInbound" title="Inbound filtering">
<t>In case the full routing table is desired from the upstream, the prefix filtering to apply is the same as the one for peers <xref target="PrefixFilteringInternetPeersInbound" /> with the exception of the default route. The default route can be desired from an upstream provider in addition to the full BGP table. In case the upstream provider is supposed to announce only the default route, a simple filter will be applied to accept only the default prefix and nothing else.</t>
</section>
<section anchor="PrefixFilteringUpstreamsOutbound" title="Outbound filtering">
<t>The filters to be applied would most likely not differ much from the ones applied for internet peers (<xref target="PrefixFilteringInternetPeersOutbound" />). But different policies could be applied in case it is desired that a particular upstream does not provide transit to all the prefixes.</t>
</section>
</section>
</section>
<section anchor="PrefixFilteringLeafNetworks" title="Prefix filtering recommendations for leaf networks">
<section anchor="PrefixFilteringLeafNetworksInbound" title="Inbound filtering">
<t>The leaf network will position the filters corresponding to the routes it is requesting from its upstream. In case a default route is requested, a simple inbound filter can be applied to accept only the default route (<xref target="PrefixFilteringDefault" />). In case the leaf network is not capable of listing the prefixes because the amount is too large (for example if it requires the full internet routing table) then it should configure filters to avoid receiving bad announcements from its upstream:
<list style="symbols">
<t><xref target="PrefixFilteringNoRoute">Prefixes not routable</xref></t>
<t><xref target="PrefixFilteringTooSpecific">Routes too specific</xref></t>
<t><xref target="PrefixFilteringSelfPrefixes">Prefixes belonging to local AS</xref></t>
<t><xref target="PrefixFilteringDefault">The default route</xref> depending if the route is requested or not</t>
</list></t>
</section>
<section anchor="PrefixFilteringLeafNetworksOutbound" title="Outbound filtering">
<t>A leaf network will most likely have a very straightforward policy: it will only announce its local routes. It can also configure the following prefixes filters described in <xref target="PrefixFilteringInternetPeersOutbound" /> to avoid announcing invalid routes to its upstream provider.</t>
</section>
</section>
</section>
<section anchor="RouteFlapDampening" title="BGP route flap dampening">
<t>The BGP route flap dampening mechanism makes it possible to give penalties to routes each time they change in the BGP routing table. Initially this mechanism was created to protect the entire internet from multiple events impacting a single network. Studies have shown that implementations of BGP route flap dampening could cause more harm than they solve problems and therefore RIPE community has in the past recommended not using BGP route flap dampening <xref target="RIPE-378" />. Works have then been conducted to propose new route flap dampening thresholds in order to make the solution "usable" <xref target="RFDusable" /> and RIPE has reviewed its recommendations in <xref target="RIPE-580" />. New thresholds have been proposed to make BGP route flap dampening usable. Authors of this document propose to follow RIPE recommendations and only use BGP route flap dampening with adjusted configured thresholds.</t>
</section>
<section anchor="MaximumPrefixes" title="Maximum prefixes on a peering">
<t>It is recommended to configure a limit on the number of routes to be accepted from a peer. Following rules are generally recommended:
<list style="symbols">
<t>From peers, it is recommended to have a limit lower than the number of routes in the internet. This will shut down the BGP peering if the peer suddenly advertises the full table. One can also configure different limits for each peer, according to the number of routes they are supposed to advertise plus some headroom to permit growth.</t>
<t>From upstreams which provide full routing, it is recommended to have a limit higher than the number of routes in the internet. A limit is still useful in order to protect the network (and in particular the routers' memory) if too many routes are sent by the upstream. The limit should be chosen according to the number of routes that can actually be handled by routers.</t>
</list>
It is important to regularly review the limits that are configured as the internet can quickly change over time. Some vendors propose mechanisms to have two thresholds: while the higher number specified will shutdown the peering, the first threshold will only trigger a log and can be used to passively adjust limits based on observations made on the network.</t>
</section>
<section anchor="ASpathFilters" title="AS-path filtering">
<t>This section is listing rules that apply to BGP AS-paths (for both 16 and 32 bits Autonomous System Numbers):
<list style="symbols">
<t>You SHOULD accept from customers only AS(4)-Paths containing ASNs belonging to (or authorized to transit through) the customer. If you can not build and generate filtering expressions to implement this, consider accepting only path lengths relevant to the type of customer you have (as in, if they are a leaf or have customers of their own), try to discourage excessive prepending in such paths.</t>
<t>You SHOULD NOT advertise prefixes with non-empty AS-path unless you intend to be transit for these prefixes.</t>
<t>You SHOULD NOT advertise prefixes with upstream AS numbers in the AS-path to your peering AS unless you intend to be transit for these prefixes.</t>
<t>You SHOULD NOT accept prefixes with private AS numbers in the AS-path except from customers. Exception: an upstream offering some particular service like black-hole origination based on a private AS number. Customers should be informed by their upstream in order to put in place ad-hoc policy to use such services.</t>
<t>You SHOULD NOT advertise prefixes with private AS numbers in the AS-path unless you are a customer using BGP without your own AS number. In that case you SHOULD use private AS numbers to advertise your prefixes to your upstream. This private AS number is usually provided by the upstream.</t>
<t>You SHOULD NOT accept prefixes when the first AS number in the AS-path is not the one of the peer unless you the peering is done toward a BGP route-server <xref target="RouteServer" /> (connection on an IXP) with transparent AS path handling. In that case this verification needs to be de-activated as the first AS number will be the one of an IXP member whereas the peer AS number will be the one of the BGP route-server.</t>
<t>You SHOULD NOT override BGP's default behavior accepting your own AS number in the AS-path. In case an exception to this is required, impacts should be studied carefully as this can create severe impact on routing.</t>
</list></t>
<t>AS-path filtering should be further analyzed when ASN renumbering is done. Such operation is common and mechanisms exist to allow smooth ASN migration <xref target="BGP-ASN-migration" />. The usual migration technique, local to a router, consists in modifying the AS-path so it is presented to a peer as if no renumbering was done. This makes it possible to change ASN of a router without reconfiguring all eBGP peers at the same time (as this operation would require synchronization with all peers attached to that router). During this renumbering operation, rules described above may be adjusted.</t>
</section>
<section anchor="NextHopFilters" title="Next-Hop Filtering">
<t>If peering on a shared network, like an IXP, BGP can advertise prefixes with a 3rd-party next-hop, thus directing packets not to the peer announcing the prefix but somewhere else.</t>
<t>This is a desirable property for BGP route-server setups <xref target="RouteServer" />, where the route-server will relay routing information, but has neither capacity nor desire to receive the actual data packets. So the BGP route-server will announce prefixes with a next-hop setting pointing to the router that originally announced the prefix to the route-server.</t>
<t>In direct peerings between ISPs, this is undesirable, as one of the peers could trick the other one to send packets into a black hole (unreachable next-hop) or to an unsuspecting 3rd party who would then have to carry the traffic. Especially for black-holing, the root cause of the problem is hard to see without inspecting BGP prefixes at the receiving router at the IXP.</t>
<t>Therefore, an inbound route policy SHOULD be applied on IXP peerings in order to set the next-hop for accepted prefixes to the BGP peer IP address (belonging to the IXP LAN) that sent the prefix (which is what "next-hop-self" would enforce on the sending side).</t>
<t>This policy MUST NOT be used on route-server peerings, or on peerings where you intentionally permit the other side to send 3rd-party next-hops.</t>
<t>This policy also MUST be adjusted if Remote Triggered Black Holing best practice (aka RTBH <xref target="RFC6666" />) is implemented. In that case one would apply a well-known BGP next-hop for routes it wants to filter (if an internet threat is observed from/to this route for example). This well known next-hop will be statically routed to a null interface. In combination with unicast RPF check, this will discard traffic from and toward this prefix. Peers can exchange information about black-holes using for example particular BGP communities. One could propagate black-holes information to its peers using agreed BGP community: when receiving a route with that community one could change the next-hop in order to create the black hole.</t>
</section>
<section anchor="CommunityFilters" title="BGP community scrubbing">
<t>Optionally we can consider the following rules on BGP AS-paths:
<list style="symbols">
<t>Scrub inbound communities with your AS number in the high-order bits – allow only those communities that customers/peers can use as a signaling mechanism</t>
<t>Do not remove other communities: your customers might need them to communicate with upstream providers. In particular do not (generally) remove the no-export community as it is usually announced by your peer for a certain purpose.</t>
</list></t>
</section>
<section anchor="FutureWork" title="Possible future work">
<t>Following propositions were made and could be added to the document:
<list style="symbols">
<t>Appendix with IRRTOOLSET examples</t>
<t>Improve IRR section and clarify who should do what and recommendations on object management</t>
<t>Change "filters" in "import/export policies"</t>
<t>Give rationale against community scrubbing</t>
<t>Integrate comments of Donald Smith regarding TTL security and MD5/TCP-AO</t>
</list></t>
</section>
<section anchor="ChangeLog" title="Change logs">
<section anchor="ChangeLogJdurandV0" title="Diffs between draft-jdurand-bgp-security-01 and draft-jdurand-bgp-security-00">
<t>Following changes have been made since previous document draft-jdurand-bgp-security-00:
<list style="symbols">
<t>"This documents" typo corrected in the former abstract</t>
<t>Add normative reference for RFC5082 in former section 3.2</t>
<t>"Non routable" changed in title of former section 4.1.1</t>
<t>Correction of typo for IPv4 loopback prefix in former section 4.1.1.1</t>
<t>Added shared transition space 100.64.0.0/10 in former section 4.1.1.1</t>
<t>Clarification that 2002::/16 6to4 prefix can cross network boundaries in former section 4.1.1.2</t>
<t>Rationale of 2000::/3 explained in former section 4.1.1.2</t>
<t>Added 3FFE::/16 prefix forgotten initially in the simplified list of prefixes that MUST not be routed by definition in former section 4.1.1.2</t>
<t>Warn that filters for prefixes not allocated by IANA MUST only be done if regular refresh is guaranteed, with some words about the IPv4 experience, in former section 4.1.2.1</t>
<t>Replace RIR database with IRR. A definition of IRR is added in former section 4.1.2.2</t>
<t>Remove any reference to anti-spoofing in former section 4.1.4</t>
<t>Clarification for IXP LAN prefix and pMTUd problem in former section 4.1.5</t>
<t>"Autonomous filters" typo (instead of Autonomous systems) corrected in the former section 4.2</t>
<t>Removal of an example for manual address validation in former section 4.2.2.1</t>
<t>RFC5735 obsoletes RFC3300</t>
<t>Ingress/Egress replaced by Inbound/Outbound in all the document</t>
</list></t>
</section>
<section anchor="ChangeLogJdurandV1" title="Diffs between draft-jdurand-bgp-security-02 and draft-jdurand-bgp-security-01">
<t>Following changes have been made since previous document draft-jdurand-bgp-security-01:
<list style="symbols">
<t>2 documentation prefixes were forgotten due to errata in RFC5735. But all prefixes were removed from that document which now point to other references for sake of not creating a new "registry" that would become outdated sooner or later</t>
<t>Change MD5 section with global TCP security session and introducing TCP-AO in former section 3.1. Added reference to BCP38</t>
<t>Added new section 3 about BGP router protection with forwarding plane ACL</t>
<t>Change text about prefix acceptable specificity in former section 4.1.3 to explain this doc does not try to make recommendations</t>
<t>Refer as much as possible to existing registries to avoid creating a new one in former section 4.1.1.1 and 4.1.1.2</t>
<t>Abstract reworded</t>
<t>6to4 exception described (only more specifics MUST be filtered)</t>
<t>More specific -> more specifics</t>
<t>should -> MUST for the prefixes an ISP needs to filter from its customers in former section 4.2.2.1</t>
<t>Added "plus some headroom to permit growth" in former section 7</t>
<t>Added new section on Next-Hop filtering</t>
</list></t>
</section>
<section anchor="ChangeLogJdurandV2" title="Diffs between draft-ietf-opsec-bgp-security-00 and draft-jdurand-bgp-security-02">
<t>Following changes have been made since previous document draft-jdurand-bgp-security-02:
<list style="symbols">
<t>Added a subsection for RTBH in next-hop section with reference to RFC6666</t>
<t>Changed last sentence of introduction</t>
<t>Many edits throughout the document</t>
<t>Added definition of tier 1 transit provider</t>
<t>Removed definition of a BGP peering</t>
<t>Removed description of routing policies for IPv6 prefixes in IANA special registry as this now contains a routing scope field</t>
<t>Added reference to RFC6598 and changed the IPv4 prefixes to be filtered by definition section</t>
<t>IXP added in accronym/definition section and only term used throughout the doc now</t>
</list></t>
</section>
<section anchor="ChangeLogOpsecV0" title="Diffs between draft-ietf-opsec-bgp-security-01 and draft-ietf-opsec-bgp-security-00">
<t>Following changes have been made since previous document draft-ietf-opsec-bgp-security-00:
<list style="symbols">
<t>Obsolete RFC2385 moved from normative to informative reference</t>
<t>Clarification of preference of TCP-AO over MD5 in former section 4.1</t>
<t>Mentioning KARP efforts in TCP session protection section in former section 4 and adding 3 RFC as informative references: 6518, 6862 and 6952</t>
<t>Removing reference to SIDR working-group</t>
<t>Better dissociating origin validation and path validation to clarify what's potentially available for deployment</t>
<t>Adding that SIDR mechanisms should be implemented in addition to the other ones mentioned throughout this document</t>
<t>Added a paragraph in former section 8 about ASN renumbering</t>
<t>Change of security considerations section</t>
<t>Added the newly created IANA IPv4 Special Purpose Address Registry instead of references to RFCs listing these addresses</t>
</list></t>
</section>
<section anchor="ChangeLogOpsecV1" title="Diffs between draft-ietf-opsec-bgp-security-02 and draft-ietf-opsec-bgp-security-01">
<t>Following changes have been made since previous document draft-ietf-opsec-bgp-security-01:
<list style="symbols">
<t>Added a reference to draft-ietf-sidr-origin-ops</t>
<t>Added a reference to RFC6811 and RFC6907</t>
<t>Changes "Most of RIR's" to "A majority of RIR's" on IRR availability</t>
<t>Various edits</t>
<t>Added NIST BGP security recommendations document</t>
<t>Added that it's possible to get info from ISPs from RADB</t>
<t>Correction of the url for IPv4 special use prefixes repository</t>
<t>Clarification of the fact only prefixes with Global Scope set to False MUST be discarded</t>
<t>IANA list could be pulled directly by routers (not just pushed on routers).</t>
<t>Warning added when prefixes are checked against IRR</t>
<t>Recommend network operators to sign their routing objects</t>
<t>Recommend network operators to publish their routing objects in IRR of their IRR when available</t>
<t>Dissociate rules for local AS and downstreams in former section 5.1.4</t>
</list></t>
</section>
</section>
<section anchor="Acknowledgements" title="Acknowledgements">
<t>The authors would like to thank the following people for their comments and support: Marc Blanchet, Ron Bonica, Randy Bush, David Freedman, Wesley George, Daniel Ginsburg, David Groves, Mike Hugues, Joel Jaeggli, Tim Kleefass, Warren Kumari, Jacques Latour, Jerome Nicolle, Hagen Paul Pfeifer, Thomas Pinaud, Carlos Pignataro, Jean Rebiffé, Donald Smith, Kotikalapudi Sriram, Matjaz Straus, Tony Tauber, Gunter Van de Velde, Sebastian Wiesinger, Matsuzaki Yoshinobu.</t>
<t>Authors would like to thank once again Gunter Van de Velde for presenting the draft at several IETF meetings in various working groups, indeed helping dissemination of this document and gathering of precious feedback.</t>
</section>
<section anchor="IANA" title="IANA Considerations">
<t>This memo includes no request to IANA.</t>
</section>
<section anchor="Security" title="Security Considerations">
<t>This document is entirely about BGP operational security. It depicts best practices that one should adopt adopt to secure its BGP infrastructure: protecting BGP router and BGP sessions, adopting consistent BGP prefix and AS-path filters and configure other options to secure the BGP network.</t>
<t>On the other hand this document doesn't aim at depicting existing BGP implementations and their potential vulnerabilities and ways they handle errors. It will not detail how protection could be enforced against attack techniques using crafted packets.</t>
</section>
</middle>
<back>
<!-- References split to informative and normative -->
<references title="Normative References">
<!-- A *really* full, totally OTT reference - Note, the "target" attribute of the
"reference": if you want a URI printed in the reference, this is where it goes. -->
<reference anchor='RFC2119'
target='http://xml.resource.org/public/rfc/html/rfc2119.html'>
<front>
<title abbrev='RFC Key Words'>Key words for use in RFCs to Indicate Requirement
Levels</title>
<author initials='S.' surname='Bradner' fullname='Scott Bradner'>
<organization>Harvard University</organization>
<address>
<postal>
<street>1350 Mass. Ave.</street>
<street>Cambridge</street>
<street>MA 02138</street>
</postal>
<phone>- +1 617 495 3864</phone>
<email>sob@harvard.edu</email>
</address>
</author>
<date year='1997' month='March' />
<area>General</area>
<keyword>keyword</keyword>
<abstract>
<t>In many standards track documents several words are used to signify
the requirements in the specification. These words are often
capitalized. This document defines these words as they should be
interpreted in IETF documents. Authors who follow these guidelines
should incorporate this phrase near the beginning of their document:
<list>
<t>
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.</t>
</list>
</t>
<t>
Note that the force of these words is modified by the requirement level of
the document in which they are used.</t>
</abstract>
</front>
<seriesInfo name='BCP' value='14' />
<seriesInfo name='RFC' value='2119' />
<format type='TXT' octets='4723' target='ftp://ftp.isi.edu/in-notes/rfc2119.txt' />
<format type='HTML' octets='14486'
target='http://xml.resource.org/public/rfc/html/rfc2119.html' />
<format type='XML' octets='5661'
target='http://xml.resource.org/public/rfc/xml/rfc2119.xml' />
</reference>
&RFC2629;
&RFC3056;
&RFC3879;
&RFC4193;
&RFC4271;
&RFC4291;
&RFC4380;
&RFC5082;
&RFC5925;
&RFC6811;
<reference anchor="RouteServer" target="http://tools.ietf.org/id/draft-ietf-idr-ix-bgp-route-server-00.txt">
<front>
<title>Internet Exchange Route Server</title>
<author>
<organization/>
</author>
<date/>
</front>
</reference>
</references>
<references title="Informative References">
&RFC2234;
&RFC2385;
&RFC2827;
&RFC3849;
&RFC4012;
&RFC4234;
&RFC5156;
&RFC5735;
&RFC5737;
&RFC6192;
&RFC6480;
&RFC6518;
&RFC6598;
&RFC6666;
&RFC6862;
&RFC6907;
&RFC6952;
<reference anchor="RIPE-378">
<front>
<title>RIPE-378 - RIPE Routing Working Group Recommendations On Route-flap Damping</title>
<author initials="P." surname="Smith">
<organization/>
</author>
<author initials="C." surname="Panigl">
<organization/>
</author>
<date month="May" year="2006" />
</front>
</reference>
<reference anchor="RIPE-399">
<front>
<title>RIPE-399 - RIPE Routing Working Group Recommendations on Route Aggregation</title>
<author initials="P." surname="Smith">
<organization/>
</author>
<author initials="R." surname="Evans">
<organization/>
</author>
<author initials="M." surname="Hughes">
<organization/>
</author>
<date month="December" year="2006" />
</front>
</reference>
<reference anchor="RIPE-532">
<front>
<title>RIPE-532 - RIPE Routing Working Group Recommendations on IPv6 Route Aggregation</title>
<author initials="P." surname="Smith">
<organization/>
</author>
<author initials="R." surname="Evans">
<organization/>
</author>
<date month="November" year="2011" />
</front>
</reference>
<reference anchor="RIPE-580">
<front>
<title>RIPE-580 - RIPE Routing Working Group Recommendations On Route-flap Damping</title>
<author initials="P." surname="Smith">
<organization/>
</author>
<author initials="R." surname="Bush">
<organization/>
</author>
<author initials="M." surname="Kuhne">
<organization/>
</author>
<author initials="C." surname="Pelsser">
<organization/>
</author>
<author initials="O." surname="Maennel">
<organization/>
</author>
<author initials="K." surname="Patel">
<organization/>
</author>
<author initials="P." surname="Mohapatra">
<organization/>
</author>
<author initials="R." surname="Evans">
<organization/>
</author>
<date month="January" year="2013" />
</front>
</reference>
<reference anchor="GertIPv6BGPFilterRecommendations" target="http://www.space.net/~gert/RIPE/ipv6-filters.html">
<front>
<title>IPv6 BGP Filter Recommendations</title>
<author initials="G." surname="Doering">
<organization/>
</author>
<date month="November" year="2009" />
</front>
</reference>
<reference anchor="IANAipv6AddressSpace" target="http://www.iana.org/assignments/ipv6-address-space/ipv6-address-space.xml">
<front>
<title>IANA IPv6 Address Space</title>
<author>
<organization/>
</author>
<date/>
</front>
</reference>
<reference anchor="IANAipv4SpecialPurposeRegistry" target="http://www.iana.org/assignments/iana-ipv4-special-registry/iana-ipv4-special-registry.xhtml">
<front>
<title>IANA IPv4 Special Purpose Address Registry</title>
<author>
<organization/>
</author>
<date/>
</front>
</reference>
<reference anchor="IANAipv6SpecialPurposeRegistry" target="http://www.iana.org/assignments/iana-ipv6-special-registry/iana-ipv6-special-registry.xml">
<front>
<title>IANA IPv6 Special Purpose Address Registry</title>
<author>
<organization/>
</author>
<date/>
</front>
</reference>
<reference anchor="IANAipv4AllocatedPrefixes" target="http://www.iana.org/assignments/ipv4-address-space/ipv4-address-space.xml">
<front>
<title>IANA IPv4 Address Space Registry</title>
<author>
<organization/>
</author>
<date/>
</front>
</reference>
<reference anchor="IANAipv6AllocatedPrefixes" target="http://www.iana.org/assignments/ipv6-unicast-address-assignments/ipv6-unicast-address-assignments.xml">
<front>
<title>IANA IPv6 Address Space Registry</title>
<author>
<organization/>
</author>
<date/>
</front>
</reference>
<reference anchor="RADB" target="http://www.radb.net">
<front>
<title>Routing Assets Database</title>
<author>
<organization/>
</author>
<date/>
</front>
</reference>
<reference anchor="RFDusable" target="http://tools.ietf.org/id/draft-ietf-idr-rfd-usable-04.txt">
<front>
<title>Making Route Flap Damping Usable</title>
<author>
<organization/>
</author>
<date/>
</front>
</reference>
<reference anchor="BGPsec-req" target="http://datatracker.ietf.org/doc/draft-ietf-sidr-bgpsec-reqs/">
<front>
<title>Security Requirements for BGP Path Validation</title>
<author>
<organization/>
</author>
<date/>
</front>
</reference>
<reference anchor="BGPsec-threat" target="http://datatracker.ietf.org/doc/draft-ietf-sidr-bgpsec-threats/">
<front>
<title>Threat Model for BGP Path Security</title>
<author>
<organization/>
</author>
<date/>
</front>
</reference>
<reference anchor="BGP-ASN-migration" target="http://datatracker.ietf.org/doc/draft-ga-idr-as-migration/">
<front>
<title>Autonomous System (AS) Migration Features and Their Effects on the BGP AS_PATH Attribute</title>
<author>
<organization/>
</author>
<date/>
</front>
</reference>
<reference anchor="RPKI-origin" target="http://tools.ietf.org/html/draft-ietf-sidr-origin-ops-23/">
<front>
<title>RPKI-Based Origin Validation Operation</title>
<author>
<organization/>
</author>
<date/>
</front>
</reference>
<reference anchor="NISTBGPsecurity" target="http://csrc.nist.gov/publications/nistpubs/800-54/SP800-54.pdf">
<front>
<title>Border Gateway Protocol Security</title>
<author fullname='Rick Kuhn'></author>
<author fullname='Kotikalapudi Sriram'></author>
<author fullname='Doug Montgomery'></author>
<date/>
</front>
</reference>
</references>
</back>
</rfc>
| PAFTECH AB 2003-2026 | 2026-04-23 15:31:31 |