--- 1/draft-ietf-6man-rfc6434-bis-02.txt 2018-02-06 11:13:22.151179444 -0800 +++ 2/draft-ietf-6man-rfc6434-bis-03.txt 2018-02-06 11:13:22.235181455 -0800 @@ -1,21 +1,21 @@ Internet Engineering Task Force T. Chown Internet-Draft Jisc Obsoletes: 6434 (if approved) J. Loughney -Intended status: Informational Intel -Expires: May 2, 2018 T. Winters - University of New Hampshire - October 29, 2017 +Intended status: Best Current Practice Intel +Expires: August 10, 2018 T. Winters + UNH-IOL + February 6, 2018 IPv6 Node Requirements - draft-ietf-6man-rfc6434-bis-02 + draft-ietf-6man-rfc6434-bis-03 Abstract This document defines requirements for IPv6 nodes. It is expected that IPv6 will be deployed in a wide range of devices and situations. Specifying the requirements for IPv6 nodes allows IPv6 to function well and interoperate in a large number of situations and deployments. This document obsoletes RFC 6434, and in turn RFC 4294. @@ -28,25 +28,25 @@ 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 https://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 May 2, 2018. + This Internet-Draft will expire on August 10, 2018. Copyright Notice - Copyright (c) 2017 IETF Trust and the persons identified as the + Copyright (c) 2018 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 (https://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 @@ -125,21 +125,21 @@ 18. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24 19. Authors and Acknowledgments . . . . . . . . . . . . . . . . . 24 19.1. Authors and Acknowledgments (Current Document) . . . . . 24 19.2. Authors and Acknowledgments from RFC 6434 . . . . . . . 24 19.3. Authors and Acknowledgments from RFC 4294 . . . . . . . 24 20. Appendix: Changes from RFC 6434 . . . . . . . . . . . . . . . 26 21. Appendix: Changes from RFC 4294 . . . . . . . . . . . . . . . 27 22. References . . . . . . . . . . . . . . . . . . . . . . . . . 29 22.1. Normative References . . . . . . . . . . . . . . . . . . 29 22.2. Informative References . . . . . . . . . . . . . . . . . 35 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 39 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 40 1. Introduction This document defines common functionality required by both IPv6 hosts and routers. Many IPv6 nodes will implement optional or additional features, but this document collects and summarizes requirements from other published Standards Track documents in one place. This document tries to avoid discussion of protocol details and @@ -198,21 +198,20 @@ IPv6 host - any node that is not a router. 2. 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]. 3. Abbreviations Used in This Document - ATM Asynchronous Transfer Mode AH Authentication Header DAD Duplicate Address Detection ESP Encapsulating Security Payload ICMP Internet Control Message Protocol IKE Internet Key Exchange MIB Management Information Base MLD Multicast Listener Discovery MTU Maximum Transmission Unit NA Neighbor Advertisement NBMA Non-Broadcast Multiple Access @@ -262,29 +261,26 @@ - Section 3 of "Basic Transition Mechanisms for IPv6 Hosts and Routers" [RFC4213] 5. IP Layer 5.1. Internet Protocol Version 6 - RFC 8200 The Internet Protocol Version 6 is specified in [RFC8200]. This specification MUST be supported. - Any unrecognized extension headers or options MUST be processed as - described in RFC 8200. - The node MUST follow the packet transmission rules in RFC 8200. + All conformant IPv6 implementations MUST be capable of sending and + receiving IPv6 packets; forwarding functionality MAY be supported. Nodes MUST always be able to send, receive, and process fragment - headers. All conformant IPv6 implementations MUST be capable of - sending and receiving IPv6 packets; the forwarding functionality MAY - be supported. Overlapping fragments MUST be handled as described in + headers. Overlapping fragments MUST be handled as described in [RFC5722]. [RFC6946] discusses IPv6 atomic fragments, and recommends that IPv6 atomic fragments are processed independently of any other fragments, to protect against fragmentation-based attacks. [RFC8021] goes further and recommends the deprecation of atomic fragments. Nodes thus MUST NOT generate atomic fragments. To mitigate a variety of potential attacks, nodes SHOULD avoid using predictable fragment Identification values in Fragment Headers, as @@ -296,43 +292,50 @@ depend only on Flow Label values being uniformly distributed. It is RECOMMENDED that source hosts support the flow label by setting the Flow Label field for all packets of a given flow to the same value chosen from an approximation to a discrete uniform distribution. 5.2. Support for IPv6 Extension Headers RFC 8200 specifies extension headers and the processing for these headers. + Any unrecognized extension headers or options MUST be processed as + described in RFC 8200. Note that where Section 4 of RFC 8200 refers + to the action to be taken when a Next Header value in the current + header is not recognized by a node, that action applies whether the + value is an unrecognized Extension Header or an unrecognized upper + layer protocol (ULP). + An IPv6 node MUST be able to process these headers. An exception is Routing Header type 0 (RH0), which was deprecated by [RFC5095] due to security concerns and which MUST be treated as an unrecognized routing type. Further, [RFC7045] adds specific requirements for processing of Extension Headers, in particular that any forwarding node along an IPv6 packet's path, which forwards the packet for any reason, SHOULD do so regardless of any extension headers that are present. [RFC7112] discusses issues with oversized IPv6 Extension Header chains, and states that when a node fragments an IPv6 datagram, it MUST include the entire IPv6 Header Chain in the First Fragment. As stated in RFC8200, extension headers (except for the Hop-by-Hop Options header) are not processed, inserted, or deleted by any node along a packet's delivery path, until the packet reaches the node (or each of the set of nodes, in the case of multicast) identified in the Destination Address field of the IPv6 header. - Should a new type of Extension Header need to be defined, its format - MUST follow the consistent format described in Section 4 of - [RFC6564]. + It should be noted that when future, new Extension Headers are + defined, the consistent format described in Section 4 of [RFC6564] + MUST be followed. 5.3. Protecting a node from excessive EH options Per RFC 8200, end hosts are expected to process all extension headers, destination options, and hop-by-hop options in a packet. Given that the only limit on the number and size of extension headers is the MTU, the processing of received packets could be considerable. It is also conceivable that a long chain of extension headers might be used as a form of denial-of-service attack. Accordingly, a host may place limits on the number and sizes of extension headers and @@ -344,23 +347,23 @@ packet should be silently discarded. The rationale is that if padding of eight or more bytes is required than the PADN option should be used. A host MAY limit number of bytes in a PADN option to be less than eight. In such a case, if a PADN option is present that has a length greater than seven then the packet should be silently discarded. The rationale for this guideline is that the purpose of padding is for alignment and eight bytes is the maximum alignment used in IPv6. - A host MAY disallow unknown options in destination options or hob-by- + A host MAY disallow unknown options in destination options or hop-by- hop options. This should be configurable where the default is to - accept unknown options and process them per RFC2460. If a packet + accept unknown options and process them per [RFC8200]. If a packet with unknown options is received and the host is configured to disallow them, then the packet should be silently discarded. A host MAY impose a limit on the maximum number of non-padding options allowed in a destination options and hop-by-hop extension headers. If this feature is supported the maximum number should be configurable and the default value SHOULD be set to eight. The limits for destination options and hop-by-hop options may be separately configurable. If a packet is received and the number of destination or hop-by-hop optines exceeds the limit, then the packet @@ -437,31 +440,30 @@ "IPv6 Host-to-Router Load Sharing" [RFC4311] includes additional recommendations on how to select from a set of available routers. [RFC4311] SHOULD be supported. 5.5. SEcure Neighbor Discovery (SEND) - RFC 3971 SEND [RFC3971] and Cryptographically Generated Addresses (CGAs) [RFC3972] provide a way to secure the message exchanges of Neighbor Discovery. SEND has the potential to address certain classes of spoofing attacks, but it does not provide specific protection for - threats from off-link attackers. It requires relatively heavyweight - provisioning, so is only likely to be used in scenarios where - security considerations are particularly important. + threats from off-link attackers. There have been relatively few implementations of SEND in common operating systems and platforms, and thus deployment experience has been limited to date. At this time, SEND is considered optional. Due to the complexity in - deploying SEND, its deployment is only likely to be considered where - nodes are operating in a particularly strict security environment. + deploying SEND, and its heavyweight provisioning, its deployment is + only likely to be considered where nodes are operating in a + particularly strict security environment. 5.6. IPv6 Router Advertisement Flags Option - RFC 5175 Router Advertisements include an 8-bit field of single-bit Router Advertisement flags. The Router Advertisement Flags Option extends the number of available flag bits by 48 bits. At the time of this writing, 6 of the original 8 single-bit flags have been assigned, while 2 remain available for future assignment. No flags have been defined that make use of the new option, and thus, strictly speaking, there is no requirement to implement the option today. However, @@ -480,114 +482,116 @@ It is strongly recommended that IPv6 nodes implement Path MTU Discovery [RFC8201], in order to discover and take advantage of path MTUs greater than 1280 octets. However, a minimal IPv6 implementation (e.g., in a boot ROM) may simply restrict itself to sending packets no larger than 1280 octets, and omit implementation of Path MTU Discovery. The rules in [RFC8200] and [RFC5722] MUST be followed for packet fragmentation and reassembly. - One operational issue with Path MTU Discovery occurs when firewalls - block ICMP Packet Too Big messages. Path MTU Discovery relies on - such messages to determine what size messages can be successfully - sent. "Packetization Layer Path MTU Discovery" [RFC4821] avoids - having a dependency on Packet Too Big messages. + One operational issue with Path MTU Discovery occurs when, contrary + to the guidance in [RFC4890], firewalls block ICMP Packet Too Big + messages. Path MTU Discovery relies on such messages to determine + what size messages can be successfully sent. "Packetization Layer + Path MTU Discovery" [RFC4821] avoids having a dependency on Packet + Too Big messages. 5.7.2. Minimum MTU considerations - While an IPv6 link MTU can be set to 1280 bytes, for IPv6 UDP in - particular, which includes DNS operation, it is recommended that the + While an IPv6 link MTU can be set to 1280 bytes, it is recommended + that for IPv6 UDP in particular, which includes DNS operation, the sender use a large MTU if they can, in order to avoid gratuitous fragmentation-caused packet drops. 5.8. ICMP for the Internet Protocol Version 6 (IPv6) - RFC 4443 ICMPv6 [RFC4443] MUST be supported. "Extended ICMP to Support Multi- Part Messages" [RFC4884] MAY be supported. 5.9. Default Router Preferences and More-Specific Routes - RFC 4191 "Default Router Preferences and More-Specific Routes" [RFC4191] provides support for nodes attached to multiple (different) networks, each providing routers that advertise themselves as default routers via Router Advertisements. In some scenarios, one router may provide connectivity to destinations the other router does not, and choosing the "wrong" default router can result in reachability failures. In order to resolve this scenario IPv6 Nodes MUST implement [RFC4191] - and SHOULD implement Type C host role. + and SHOULD implement the Type C host role defined in RFC4191. 5.10. First-Hop Router Selection - RFC 8028 In multihomed scenarios, where a host has more than one prefix, each allocated by an upstream network that is assumed to implement BCP 38 ingress filtering, the host may have multiple routers to choose from. Hosts that may be deployed in such multihomed environments SHOULD follow the guidance given in [RFC8028]. 5.11. Multicast Listener Discovery (MLD) for IPv6 - RFC 3810 Nodes that need to join multicast groups MUST support MLDv2 [RFC3810]. MLD is needed by any node that is expected to receive and process multicast traffic and in particular MLDv2 is required for support for source-specific multicast (SSM) as per [RFC4607]. - Previous version of this document only required MLDv1 to be - implemented on all nodes. Since participation of any MLDv1-only + Previous versions of this document only required MLDv1 ([RFC2710]) to + be implemented on all nodes. Since participation of any MLDv1-only nodes on a link require that all other nodeas on the link then operate in version 1 compatibility mode, the requirement to support MLDv2 on all nodes was upgraded to a MUST. Further, SSM is now the preferred multicast distribution method, rather than ASM. Note that Neighbor Discovery (as used on most link types -- see Section 5.4) depends on multicast and requires that nodes join Solicited Node multicast addresses. 5.12. Explicit Congestion Notification (ECN) - RFC 3168 - An ECN-aware router may set a mark in the IP header instead of - dropping a packet in order to signal impending congestion. The + An ECN-aware router may set a mark in the IP header in order to + signal impending congestion, rather than dropping a packet. The receiver of the packet echoes the congestion indication to the sender, which can then reduce its transmission rate as if it detected a dropped packet. Nodes that may be deployed in environments where they would benefit from such early congestion notification SHOULD implement [RFC3168]. - - ** BIS - but note draft-ietf-tsvwg-ecn-experimentation-03, e.g., - nonce comment + In such cases, the updates presented in [RFC8311] may also be + relevant. 6. Addressing and Address Configuration 6.1. IP Version 6 Addressing Architecture - RFC 4291 The IPv6 Addressing Architecture [RFC4291] MUST be supported. The current IPv6 Address Architecture is based on a 64-bit boundary for subnet prefixes. The reasoning behind this decision is documented in [RFC7421]. 6.2. Host Address Availability Recommendations Hosts may be configured with addresses through a variety of methods, including SLAAC, DHCPv6, or manual configuration. [RFC7934] recommends that networks provide general-purpose end hosts with multiple global IPv6 addresses when they attach, and it - describes the benefits of and the options for doing so. + describes the benefits of and the options for doing so. Router + SHOULD support [RFC7934] for assigning multiple address to a host. + Host SHOULD support assigning multiple addresses as described in + [RFC7934]. Nodes SHOULD support the capability to be assigned a prefix per host - as documented in Unique IPv6 Prefix Per Host - [I-D.ietf-v6ops-unique-ipv6-prefix-per-host]. Such an approach can - offer improved host isolation and enhanced subscriber management on - shared network segments. + as documented in [RFC8273]. Such an approach can offer improved host + isolation and enhanced subscriber management on shared network + segments. 6.3. IPv6 Stateless Address Autoconfiguration - RFC 4862 Hosts MUST support IPv6 Stateless Address Autoconfiguration. It is recommended, as described in [RFC8064], that unless there is a specific requirement for MAC addresses to be embedded in an IID, nodes follow the procedure in [RFC7217] to generate SLAAC-based addresses, rather than using [RFC4862]. Addresses generated through RFC7217 will be the same whenever a given device (re)appears on the same subnet (with a specific IPv6 prefix), but the IID will vary on @@ -638,21 +642,22 @@ IID will see that IID remain the same on any visited network, even though the network prefix part changes. Thus it is possible for 3rd party devices such nodes communicate with to track the activities of the node as it moves around the network. Privacy Extensions for Stateless Address Autoconfiguration [RFC4941] address this concern by allowing nodes to configure an additional temporary address where the IID is effectively randomly generated. Privacy addresses are then used as source addresses for new communications initiated by the node. - [RFC7721] discusses general privacy issues with IPv6 addressing. + General issues regarding privacy issues for IPv6 addressing are + discussed in [RFC7721]. RFC 4941 SHOULD be supported. In some scenarios, such as dedicated servers in a data center, it provides limited or no benefit, or may complicate network management. Thus devices implementing this specification MUST provide a way for the end user to explicitly enable or disable the use of such temporary addresses. Note that RFC4941 can be used independently of traditional SLAAC, or of RFC7217-based SLAAC. @@ -651,53 +656,51 @@ servers in a data center, it provides limited or no benefit, or may complicate network management. Thus devices implementing this specification MUST provide a way for the end user to explicitly enable or disable the use of such temporary addresses. Note that RFC4941 can be used independently of traditional SLAAC, or of RFC7217-based SLAAC. Implementers of RFC 4941 should be aware that certain addresses are reserved and should not be chosen for use as temporary addresses. - Consult "Reserved IPv6 Interface Identifiers" [RFC5453] for more details. 6.5. Stateful Address Autoconfiguration (DHCPv6) - RFC 3315 DHCPv6 [RFC3315] can be used to obtain and configure addresses. In general, a network may provide for the configuration of addresses - through Router Advertisements, DHCPv6, or both. There will be a wide - range of IPv6 deployment models and differences in address assignment - requirements, some of which may require DHCPv6 for stateful address - assignment. Consequently, all hosts SHOULD implement address - configuration via DHCPv6. + through SLAAC, DHCPv6, or both. There will be a wide range of IPv6 + deployment models and differences in address assignment requirements, + some of which may require DHCPv6 for stateful address assignment. + Consequently, all hosts SHOULD implement address configuration via + DHCPv6. - In the absence of a router, IPv6 nodes using DHCP for address - assignment MAY initiate DHCP to obtain IPv6 addresses and other - configuration information, as described in Section 5.5.2 of - [RFC4862]. + In the absence of observed Router Advertisement messages, IPv6 nodes + MAY initiate DHCP to obtain IPv6 addresses and other configuration + information, as described in Section 5.5.2 of [RFC4862]. Where devices are likely to be carried by users and attached to multiple visisted networks, DHCPv6 client anonymity profiles SHOULD - be supported as described in [RFC7844] to minimise the discolosure of + be supported as described in [RFC7844] to minimise the disclosure of identifying information. Section 5 of RFC7844 describes operational considerations on the use of such anonymity profiles. 6.6. Default Address Selection for IPv6 - RFC 6724 IPv6 nodes will invariably have multiple addresses configured simultaneously, and thus will need to choose which addresses to use for which communications. The rules specified in the Default Address - Selection for IPv6 [RFC6724] document MUST be implemented. Since - [RFC8028] updates rule 5.5 from [RFC6724] implementations SHOULD - implement this rule. + Selection for IPv6 [RFC6724] document MUST be implemented. [RFC8028] + updates rule 5.5 from [RFC6724]; implementations SHOULD implement + this rule. 7. DNS DNS is described in [RFC1034], [RFC1035], [RFC3363], and [RFC3596]. Not all nodes will need to resolve names; those that will never need to resolve DNS names do not need to implement resolver functionality. However, the ability to resolve names is a basic infrastructure capability on which applications rely, and most nodes will need to provide support. All nodes SHOULD implement stub-resolver [RFC1034] functionality, as in [RFC1034], Section 5.3.1, with support for: @@ -712,42 +715,46 @@ [RFC4033] [RFC4034] [RFC4035]. A6 Resource Records, which were only ever defined with Experimental status in [RFC3363], are now classified as Historic, as per [RFC6563]. 8. Configuring Non-Address Information 8.1. DHCP for Other Configuration Information - IPv6 nodes use DHCP [RFC3315] to obtain address configuration - information (see Section 6.5) and to obtain additional (non-address) - configuration. If a host implementation supports applications or - other protocols that require configuration that is only available via - DHCP, hosts SHOULD implement DHCP. For specialized devices on which - no such configuration need is present, DHCP may not be necessary. + DHCP [RFC3315] Specifies a mechanism for IPv6 nodes to obtain address + configuration information (see Section 6.5) and to obtain additional + (non-address) configuration. If a host implementation supports + applications or other protocols that require configuration that is + only available via DHCP, hosts SHOULD implement DHCP. For + specialized devices on which no such configuration need is present, + DHCP may not be necessary. An IPv6 node can use the subset of DHCP (described in [RFC3736]) to obtain other configuration information. + If an IPv6 node implements DHCP it MUST implement the DNS options + [RFC3646] as most deployments will expect this options are available. + 8.2. Router Advertisements and Default Gateway There is no defined DHCPv6 Gateway option. Nodes using the Dynamic Host Configuration Protocol for IPv6 (DHCPv6) are thus expected to determine their default router information and on-link prefix information from received Router Advertisements. 8.3. IPv6 Router Advertisement Options for DNS Configuration - RFC 8106 - Router Advertisements have historically limited options to those that - are critical to basic IPv6 functioning. Originally, DNS + Router Advertisement Options have historically been limited to those + that are critical to basic IPv6 functionality. Originally, DNS configuration was not included as an RA option, and DHCP was the recommended way to obtain DNS configuration information. Over time, the thinking surrounding such an option has evolved. It is now generally recognized that few nodes can function adequately without having access to a working DNS resolver, and thus a Standards Track document has been published to provide this capability [RFC8106]. Implementations MUST include support for the DNS RA option [RFC8106]. 8.4. DHCP Options versus Router Advertisement Options for Host @@ -883,35 +890,41 @@ This section describes the specification for security for IPv6 nodes. Achieving security in practice is a complex undertaking. Operational procedures, protocols, key distribution mechanisms, certificate management approaches, etc., are all components that impact the level of security actually achieved in practice. More importantly, deficiencies or a poor fit in any one individual component can significantly reduce the overall effectiveness of a particular security approach. - IPsec provides channel security at the Internet layer, making it - possible to provide secure communication for all (or a subset of) - communication flows at the IP layer between pairs of internet nodes. - IPsec provides sufficient flexibility and granularity that individual - TCP connections can (selectively) be protected, etc. + IPsec either can provide end-to-end security between nodes or or can + provide channel security (for example, via a site-to-site IPsec VPN), + making it possible to provide secure communication for all (or a + subset of) communication flows at the IP layer between pairs of + internet nodes. IPsec has two standard operating modes, Tunnel-mode + and Transport-mode. In Tunnel-mode, IPsec provides network-layer + security and protects an entire IP packet by encapsulating the + orginal IP packet and then pre-pending a new IP header. In + Transport-mode, IPsec provides security for the transport-layer (and + above) by encapsulating only the transport-layer (and above) portion + of the IP packet (i.e., without adding a 2nd IP header). Although IPsec can be used with manual keying in some cases, such usage has limited applicability and is not recommended. A range of security technologies and approaches proliferate today - (e.g., IPsec, Transport Layer Security (TLS), Secure SHell (SSH), - etc.) No one approach has emerged as an ideal technology for all - needs and environments. Moreover, IPsec is not viewed as the ideal - security technology in all cases and is unlikely to displace the - others. + (e.g., IPsec, Transport Layer Security (TLS), Secure SHell (SSH), SSL + VPNS, etc.) No one approach has emerged as an ideal technology for + all needs and environments. Moreover, IPsec is not viewed as the + ideal security technology in all cases and is unlikely to displace + the others. Previously, IPv6 mandated implementation of IPsec and recommended the key management approach of IKE. This document updates that recommendation by making support of the IPsec Architecture [RFC4301] a SHOULD for all IPv6 nodes. Note that the IPsec Architecture requires (e.g., Section 4.5 of RFC 4301) the implementation of both manual and automatic key management. Currently, the default automated key management protocol to implement is IKEv2 [RFC7296]. This document recognizes that there exists a range of device types @@ -951,34 +964,33 @@ The current set of mandatory-to-implement algorithms for IKEv2 are defined in "Cryptographic Algorithms for Use in the Internet Key Exchange Version 2 (IKEv2)" [RFC8247]. IPv6 nodes implementing IKEv2 MUST conform to the requirements in [RFC8247] and/or any future updates or replacements to [RFC8247]. 14. Router-Specific Functionality This section defines general host considerations for IPv6 nodes that act as routers. Currently, this section does not discuss detailed - routing-specific requirements; for the case of typical home routers, + routing-specific requirements. For the case of typical home routers, [RFC7084] defines basic requirements for customer edge routers. Further recommendations on router-specific functionality can be found in [I-D.ietf-v6ops-ipv6rtr-reqs]. 14.1. IPv6 Router Alert Option - RFC 2711 The IPv6 Router Alert Option [RFC2711] is an optional IPv6 Hop-by-Hop Header that is used in conjunction with some protocols (e.g., RSVP - [RFC2205] or Multicast Listener Discovery (MLD) [RFC2710]). The - Router Alert option will need to be implemented whenever protocols - that mandate its usage (e.g., MLD) are implemented. See - Section 5.11. + [RFC2205] or Multicast Listener Discovery (MLDv2) [RFC3810]). The + Router Alert option will need to be implemented whenever such + protocols that mandate its use are implemented. See Section 5.11. 14.2. Neighbor Discovery for IPv6 - RFC 4861 Sending Router Advertisements and processing Router Solicitations MUST be supported. Section 7 of [RFC6275] includes some mobility-specific extensions to Neighbor Discovery. Routers SHOULD implement Sections 7.3 and 7.5, even if they do not implement Home Agent functionality. @@ -986,22 +998,22 @@ A single DHCP server ([RFC3315] or [RFC4862]) can provide configuration information to devices directly attached to a shared link, as well as to devices located elsewhere within a site. Communication between a client and a DHCP server located on different links requires the use of DHCP relay agents on routers. In simple deployments, consisting of a single router and either a single LAN or multiple LANs attached to the single router, together with a WAN connection, a DHCP server embedded within the router is - one common deployment scenario (e.g., [RFC7084]). However, there is - no need for relay agents in such scenarios. + one common deployment scenario (e.g., [RFC7084]). There is no need + for relay agents in such scenarios. In more complex deployment scenarios, such as within enterprise or service provider networks, the use of DHCP requires some level of configuration, in order to configure relay agents, DHCP servers, etc. In such environments, the DHCP server might even be run on a traditional server, rather than as part of a router. Because of the wide range of deployment scenarios, support for DHCP server functionality on routers is optional. However, routers targeted for deployment within more complex scenarios (as described @@ -1027,37 +1039,36 @@ compromises are made, the interoperability of devices should be strongly considered, paticularly where this may impact other nodes on the same link, e.g., only supporting MLDv1 will affect other nodes. The IETF 6LowPAN (IPv6 over Low Power LWPAN) WG defined six RFCs, including a general overview and problem statement ([RFC4919], the means by which IPv6 packets are transmitted over IEEE 802.15.4 networks [RFC4944] and ND optimisations for that medium [RFC6775]. If an IPv6 node is concerned about the impact of IPv6 message power - consumption, it MAY want to implement the recommendations in + consumption, it SHOULD want to implement the recommendations in [RFC7772]. 16. Network Management Network management MAY be supported by IPv6 nodes. However, for IPv6 nodes that are embedded devices, network management may be the only possible way of controlling these nodes. A node supporting network management SHOULD support NETCONF [RFC6241] and SNMP configuration [RFC3411]. 16.1. Management Information Base (MIB) Modules - IPv6 MIB have been updated since the last release of the document, - [RFC8096] obseletes several MIBs, the nodes need to not support any - longer. + IPv6 MIBs have been updated since the last release of the document; + [RFC8096] obseletes several MIBs, which nodes need no longer support. The following two MIB modules SHOULD be supported by nodes that support a Simple Network Management Protocol (SNMP) agent. 16.1.1. IP Forwarding Table MIB The IP Forwarding Table MIB [RFC4292] SHOULD be supported by nodes that support an SNMP agent. 16.1.2. Management Information Base for the Internet Protocol (IP) @@ -1167,78 +1178,82 @@ 20. Appendix: Changes from RFC 6434 There have been many editorial clarifications as well as significant additions and updates. While this section highlights some of the changes, readers should not rely on this section for a comprehensive list of all changes. 1. Restructured sections - 2. Added 6LoWPAN to link layers. - - 3. Removed DOD IPv6 Profile updates. - - 4. Updated to state MLDv2 support is a MUST. + 2. Added 6LoWPAN to link layers as it has some deployment. - 5. Require DNS RA Options, RFC8106 is a MUST. + 3. Removed DOD IPv6 Profile as it hasn't been updated. - 6. Added section on constrained devices. + 4. Updated to MLDv2 support to a MUST since nodes are restricted if + MLDv1 is used. - 7. Added text on RFC7934, address availability to hosts. + 5. Require DNS RA Options so SLAAC-only devices can get DNS, + RFC8106 is a MUST. - 8. Added text on RFC7844, anonymity profiles for DHCPv6 clients. + 6. Require RFC3646 DNS Options for DHCPv6 implementations. - 9. mDNS and DNS-SD added. + 7. Added section on constrained devices. - 10. Added RFC8028 as a SHOULD. + 8. Added text on RFC7934, address availability to hosts (SHOULD). - 11. Added ECN RFC3168 as a SHOULD. + 9. Added text on RFC7844, anonymity profiles for DHCPv6 clients. - 12. Added reference to RFC7123. + 10. mDNS and DNS-SD added as updated service discovery. - 13. Removed Jumbograms RFC2675. + 11. Added RFC8028 as a SHOULD as a method for solving multi-prefix + network - 14. Updated RFC2460 to 8200. + 12. Added ECN RFC3168 as a SHOULD, since recent reports have shown + this as useful, and added a note on RFC8311, which is related. - 15. Updated RFC1981 to 8201. + 13. Added reference to RFC7123 for Security over IPv4-only networks - 16. Updated RFC1981 to 8201. + 14. Removed Jumbograms RFC2675 as they aren't deployed. - 17. Updated RFC7321 to 8221. + 15. Updated Obseleted RFCs to the new version of the RFC including + 2460, 1981, 7321, 4307 - 18. Updated RFC4307 to 8247. + 16. Added RFC7772 for power comsumptions considerations - 19. Added RFC7772 for power comsumptions + 17. Added why /64 boundries for more detail - RFC 7421 - 20. Added why /64 boundries - RFC 7421 + 18. Added a Unique IPv6 Prefix per Host to support currently + deployed IPv6 networks - 21. Added a Unique IPv6 PRefix per Host - 22. Clarified RFC7066 was snapshot for 3GPP + 19. Clarified RFC7066 was snapshot for 3GPP - 23. Updated 4191 as a MUST, SHOULD for Type C Host. + 20. Updated 4191 as a MUST, SHOULD for Type C Host as it helps solve + multi-prefix problem - 24. Removed IPv6 over ATM + 21. Removed IPv6 over ATM since there aren't many deployments - 25. Added a note in Section 6.6 for RFC6724 Section 5.5/ + 22. Added a note in Section 6.6 for RFC6724 Section 5.5/ - 26. Added MUST for BCP 198 + 23. Added MUST for BCP 198 for forwarding IPv6 packets - 27. Added reference to draft-ietf-v6ops-ipv6rtr-reqs + 24. Added reference to draft-ietf-v6ops-ipv6rtr-reqs as it has more + recommendations for a Router - 28. Added reference to RFC8064 + 25. Added reference to RFC8064 for stable address creation. - 29. Made RFC8028 normative + 26. Added text on protection from excessive EH options - 30. Added text on protection from excessive EH options + 27. Added text on dangers of 1280 MTU UDP, esp. wrt DNS traffic - 31. Added text on dangers of 1280 MTU UDP, esp. wrt DNS traffic + 28. Added text to clarify RFC8200 behaviour for unrecognized EHs or + unrecognized ULPs 21. Appendix: Changes from RFC 4294 There have been many editorial clarifications as well as significant additions and updates. While this section highlights some of the changes, readers should not rely on this section for a comprehensive list of all changes. 1. Updated the Introduction to indicate that this document is an applicability statement and is aimed at general nodes. @@ -1598,31 +1613,31 @@ Payload (ESP) and Authentication Header (AH)", RFC 8221, DOI 10.17487/RFC8221, October 2017, . [RFC8247] Nir, Y., Kivinen, T., Wouters, P., and D. Migault, "Algorithm Implementation Requirements and Usage Guidance for the Internet Key Exchange Protocol Version 2 (IKEv2)", RFC 8247, DOI 10.17487/RFC8247, September 2017, . -22.2. Informative References + [RFC8311] Black, D., "Relaxing Restrictions on Explicit Congestion + Notification (ECN) Experimentation", RFC 8311, + DOI 10.17487/RFC8311, January 2018, + . - [I-D.ietf-v6ops-unique-ipv6-prefix-per-host] - Brzozowski, J. and G. Velde, "Unique IPv6 Prefix Per - Host", draft-ietf-v6ops-unique-ipv6-prefix-per-host-13 - (work in progress), October 2017. +22.2. Informative References [I-D.ietf-v6ops-ipv6rtr-reqs] Kahn, Z., Brzozowski, J., and R. White, "Requirements for - IPv6 Routers", draft-ietf-v6ops-ipv6rtr-reqs-00 (work in - progress), May 2017. + IPv6 Routers", draft-ietf-v6ops-ipv6rtr-reqs-01 (work in + progress), January 2018. [RFC0793] Postel, J., "Transmission Control Protocol", STD 7, RFC 793, DOI 10.17487/RFC0793, September 1981, . [RFC2205] Braden, R., Ed., Zhang, L., Berson, S., Herzog, S., and S. Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 Functional Specification", RFC 2205, DOI 10.17487/RFC2205, September 1997, . @@ -1653,20 +1668,25 @@ [RFC3493] Gilligan, R., Thomson, S., Bound, J., McCann, J., and W. Stevens, "Basic Socket Interface Extensions for IPv6", RFC 3493, DOI 10.17487/RFC3493, February 2003, . [RFC3542] Stevens, W., Thomas, M., Nordmark, E., and T. Jinmei, "Advanced Sockets Application Program Interface (API) for IPv6", RFC 3542, DOI 10.17487/RFC3542, May 2003, . + [RFC3646] Droms, R., Ed., "DNS Configuration options for Dynamic + Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3646, + DOI 10.17487/RFC3646, December 2003, + . + [RFC3678] Thaler, D., Fenner, B., and B. Quinn, "Socket Interface Extensions for Multicast Source Filters", RFC 3678, DOI 10.17487/RFC3678, January 2004, . [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July 2011, . [RFC3776] Arkko, J., Devarapalli, V., and F. Dupont, "Using IPsec to @@ -1716,20 +1736,25 @@ [RFC4877] Devarapalli, V. and F. Dupont, "Mobile IPv6 Operation with IKEv2 and the Revised IPsec Architecture", RFC 4877, DOI 10.17487/RFC4877, April 2007, . [RFC4884] Bonica, R., Gan, D., Tappan, D., and C. Pignataro, "Extended ICMP to Support Multi-Part Messages", RFC 4884, DOI 10.17487/RFC4884, April 2007, . + [RFC4890] Davies, E. and J. Mohacsi, "Recommendations for Filtering + ICMPv6 Messages in Firewalls", RFC 4890, + DOI 10.17487/RFC4890, May 2007, + . + [RFC4919] Kushalnagar, N., Montenegro, G., and C. Schumacher, "IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs): Overview, Assumptions, Problem Statement, and Goals", RFC 4919, DOI 10.17487/RFC4919, August 2007, . [RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler, "Transmission of IPv6 Packets over IEEE 802.15.4 Networks", RFC 4944, DOI 10.17487/RFC4944, September 2007, . @@ -1800,20 +1825,24 @@ [RFC7934] Colitti, L., Cerf, V., Cheshire, S., and D. Schinazi, "Host Address Availability Recommendations", BCP 204, RFC 7934, DOI 10.17487/RFC7934, July 2016, . [RFC8096] Fenner, B., "The IPv6-Specific MIB Modules Are Obsolete", RFC 8096, DOI 10.17487/RFC8096, April 2017, . + [RFC8273] Brzozowski, J. and G. Van de Velde, "Unique IPv6 Prefix + per Host", RFC 8273, DOI 10.17487/RFC8273, December 2017, + . + [POSIX] IEEE, "IEEE Std. 1003.1-2008 Standard for Information Technology -- Portable Operating System Interface (POSIX), ISO/IEC 9945:2009", . [USGv6] National Institute of Standards and Technology, "A Profile for IPv6 in the U.S. Government - Version 1.0", July 2008, . Authors' Addresses @@ -1817,24 +1846,24 @@ Authors' Addresses Tim Chown Jisc Lumen House, Library Avenue Harwell Oxford, Didcot OX11 0SG United Kingdom Email: tim.chown@jisc.ac.uk + John Loughney Intel Santa Clara, CA USA Email: john.loughney@gmail.com Timothy Winters - University of New Hampshire - InterOperability Laboratory - Durham NH + University of New Hampshire, Interoperability Lab (UNH-IOL) + Durham, NH United States Email: twinters@iol.unh.edu