YANG Data Model for IPv6 Neighbor Discovery
draft-ietf-6man-ipv6-neighbor-discovery-yang-08
| Document | Type | Active Internet-Draft (6man WG) | |
|---|---|---|---|
| Authors | Fan Zhang , Yongqing Zhu , Bo Wu , Jiayuan Hu | ||
| Last updated | 2026-09-25 (Latest revision 2026-09-01) | ||
| Replaces | draft-zhang-6man-ipv6-address-resolution-yang | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Intended RFC status | Proposed Standard | ||
| Formats | |||
| Yang Validation | 0 errors, 0 warnings | ||
| Reviews |
INTDIR IETF Last Call review
by Carlos Pignataro
Ready w/issues
OPSDIR IETF Last Call review
by Tina Tsou
Has issues
YANGDOCTORS Early review
(of
-02)
by Ebben Aries
Almost ready
|
||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Jen Linkova | ||
| Shepherd write-up | Show Last changed 2026-08-12 | ||
| IESG | IESG state | Waiting for AD Go-Ahead::Revised I-D Needed | |
| Action Holders | |||
| Consensus boilerplate | Yes | ||
| Telechat date |
(None)
Needs 9 more YES or NO OBJECTION positions to pass. |
||
| Responsible AD | Éric Vyncke | ||
| Send notices to | furry13@gmail.com | ||
| IANA | IANA review state | IANA OK - Actions Needed | |
| IANA expert review state | Expert Reviews OK |
draft-ietf-6man-ipv6-neighbor-discovery-yang-08
6MAN F. Zhang
Internet-Draft Y. Zhu
Intended status: Standards Track China Telecom
Expires: 5 March 2027 B. Wu
Huawei
J. Hu
China Telecom
1 September 2026
YANG Data Model for IPv6 Neighbor Discovery
draft-ietf-6man-ipv6-neighbor-discovery-yang-08
Abstract
This document defines a YANG data model to configure and manage IPv6
Neighbor Discovery (ND) and related functions, including IPv6 address
resolution, redirect function, proxy Neighbor Advertisement, Neighbor
Unreachability Detection (NUD), Duplicate Address Detection (DAD),
and Enhanced Duplicate Address Detection.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at 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 5 March 2027.
Copyright Notice
Copyright (c) 2026 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
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extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Tree Diagrams . . . . . . . . . . . . . . . . . . . . . . 4
2. Design of the Data Model . . . . . . . . . . . . . . . . . . 4
2.1. IPv6 Address Resolution and Redirect Function . . . . . . 4
2.2. Neighbor Unreachability Detection . . . . . . . . . . . . 5
2.3. Proxy Neighbor Advertisement . . . . . . . . . . . . . . 5
2.4. Duplicate Address Detection . . . . . . . . . . . . . . . 5
2.5. IPv6 Neighbor Discovery Data Model . . . . . . . . . . . 5
3. IPv6 Neighbor Discovery YANG Module . . . . . . . . . . . . . 7
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
5. Security Considerations . . . . . . . . . . . . . . . . . . . 16
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 17
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 17
7.1. Normative References . . . . . . . . . . . . . . . . . . 17
7.2. Informative References . . . . . . . . . . . . . . . . . 18
Appendix A. Example Proxy Neighbor Advertisement, Redirect, NUD,
and DAD Configuration . . . . . . . . . . . . . . . . . . 20
Appendix B. Coverage of IPv6 ND Functions in YANG Modules . . . 22
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 26
1. Introduction
This document defines a YANG [RFC7950] data model "ietf-ipv6-nd" to
configure and manage IPv6 Neighbor Discovery (ND) and related
functions, including IPv6 address resolution [RFC4861], redirect
function [RFC4861], proxy Neighbor Advertisement [RFC4861], Neighbor
Unreachability Detection (NUD) [RFC4861], Duplicate Address Detection
(DAD) [RFC4862], and Enhanced Duplicate Address Detection [RFC7527].
Basic neighbor management functionality is supported by the "ietf-ip"
YANG data model [RFC8344], and there is already a draft
[I-D.ietf-intarea-arp-yang-model] extending the basic ARP YANG
functionality to cover optional ARP features and related statistics,
which applies only to IPv4. Thus, an extension for IPv6 is required
to maintain the IPv6 Neighbor Cache entries.
[RFC4861] specifies the Neighbor Discovery protocol for IPv6, and
[RFC4862] specifies related functions. This document covers IPv6
address resolution [RFC4861], redirect function [RFC4861], proxy
Neighbor Advertisement [RFC4861], NUD [RFC4861], DAD [RFC4862], and
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Enhanced DAD [RFC7527]. Other functions, such as Router and Prefix
Discovery [RFC4861] are covered by submodule "ietf-ipv6-router-
advertisements" in [RFC8349], and static neighbor cache entries and
Stateless Address Autoconfiguration [RFC4862] are covered by module
"ietf-ip" in [RFC8344].
Neighbor Discovery Optimization for 6LoWPANs [RFC6775] and other
related extensions, such as those specified in [RFC8505], [RFC8928],
and [RFC9010], are out of scope of this document.
1.1. Terminology
The following terms are defined in [RFC8342]:
* configuration
* system state
* operational state
The following terms are defined in [RFC7950]:
* augment
* container
* data model
* data node
* leaf
* list
* module
* schema tree
The following terms are defined in [RFC4861]:
* Neighbor Discovery
* Neighbor Advertisement
* proxy Neighbor Advertisement
* Neighbor Unreachability Detection
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The following term is defined in [RFC4862]:
* Duplicate Address Detection
* Stateless Address Autoconfiguration
The following term is defined in [RFC7527]:
* Enhanced Duplicate Address Detection
1.2. Tree Diagrams
Tree diagrams used in this document follow the notation defined in
[RFC8340].
2. Design of the Data Model
The YANG data model for IPv6 ND augments the "ietf-ip" [RFC8344] to
provide per-interface configuration and management of IPv6 address
resolution and redirect functions based on the IPv6 ND protocol, as
well as other related functions, including proxy Neighbor
Advertisement, NUD, DAD, and Enhanced DAD.
Note that the features related to ICMP Router and Prefix Discovery
are outside the scope of this module, since they have already been
defined in the submodule "ietf-ipv6-router-advertisements" [RFC8349].
Static neighbor cache entries and stateless address autoconfiguration
[RFC4862] are also out of scope, as they are covered by "ietf-
ip"[RFC8344].
2.1. IPv6 Address Resolution and Redirect Function
The data model augments the "/if:interfaces/if:interface/ip:ipv6"
path defined in the "ietf-ip" module [RFC8344] for IPv6 ND protocol
[RFC4861].
The "retrans-timer" leaf defines the interval of retransmitting
Neighbor Solicitation messages when a node tries to learn the link-
layer address of another node.
The "redirect" leaf enables the sending of Redirect messages.
The "statistics" container defines a collection of per-interface
operational statistics for each type of IPv6 ND messages.
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2.2. Neighbor Unreachability Detection
The "reachable-time" leaf defines the time to confirm a neighbor's
reachability for NUD. A neighbor's state changes from REACHABLE to
STALE when there is no other reachability confirmation from the
neighbor within the "reachable-time".
The "retrans-timer" leaf also indicates the interval for
retransmitting Neighbor Solicitation messages used by NUD.
2.3. Proxy Neighbor Advertisement
The "proxy-na" leaf augmenting "ietf-ip" [RFC8344] defines the
configurations of proxy Neighbor Advertisements [RFC4861], which
indicate that a router is willing to accept packets not explicitly
addressed to itself. After receiving a Neighbor Solicitation message
whose destination address is not its own IPv6 address, a proxy router
replies to the source with a Neighbor Advertisement message carrying
its own link-layer address and the IPv6 address of the original
destination.
2.4. Duplicate Address Detection
The "dup-addr-detect-transmits" leaf, as defined in "ietf-ip"
[RFC8344], indicates the number of consecutive Neighbor Solicitation
messages sent while performing Duplicate Address Detection (DAD)
[RFC4862]. The value of "dup-addr-detect-transmits" can be set to 0
to disable DAD.
The "retrans-timer" leaf also indicates the interval for
retransmitting Neighbor Solicitation messages during DAD.
The "enhanced-dad" container augmenting "ietf-ip" [RFC8344] defines
the configurations for enhanced DAD [RFC7527], which is used to
automatically detect the looped-back IPv6 ND messages used in DAD.
The "auto-resolve" leaf enables automated action when a duplicate is
detected. When enabled, a trusted router may log a system management
message, drop the received ND message, and block the untrusted IPv6
host nodes from which the duplicate NS (DAD) or NA message was
received.
2.5. IPv6 Neighbor Discovery Data Model
This document defines the YANG module "ietf-ipv6-nd", which has the
following structure.
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module: ietf-ipv6-nd
augment /if:interfaces/if:interface/ip:ipv6:
+--rw nd
+--rw reachable-time? uint32
+--rw retrans-timer? uint32
+--rw redirect? boolean
+--rw proxy-na? boolean
+--rw enhanced-dad
| +--rw enable? boolean
| +--rw auto-resolve? boolean
+--ro statistics
+--ro ns-stats
| +--ro in-pkts? yang:counter64
| +--ro out-pkts? yang:counter64
| +--ro drop-pkts? yang:counter64
| +--ro in-unicast-pkts? yang:counter64
| +--ro in-multicast-pkts? yang:counter64
| +--ro out-unicast-pkts? yang:counter64
| +--ro out-multicast-pkts? yang:counter64
| +--ro drop-bad-code-pkts? yang:counter64
| +--ro drop-bad-hoplimit-pkts? yang:counter64
| +--ro drop-bad-len-pkts? yang:counter64
| +--ro drop-bad-option-pkts? yang:counter64
| +--ro drop-checksum-err-pkts? yang:counter64
| +--ro drop-fragmented-pkts? yang:counter64
| +--ro out-nud-pkts? yang:counter64
+--ro na-stats
| +--ro in-pkts? yang:counter64
| +--ro out-pkts? yang:counter64
| +--ro drop-pkts? yang:counter64
| +--ro in-unicast-pkts? yang:counter64
| +--ro in-multicast-pkts? yang:counter64
| +--ro out-unicast-pkts? yang:counter64
| +--ro out-multicast-pkts? yang:counter64
| +--ro drop-bad-code-pkts? yang:counter64
| +--ro drop-bad-hoplimit-pkts? yang:counter64
| +--ro drop-bad-len-pkts? yang:counter64
| +--ro drop-bad-option-pkts? yang:counter64
| +--ro drop-checksum-err-pkts? yang:counter64
| +--ro drop-fragmented-pkts? yang:counter64
| +--ro in-solicited-pkts? yang:counter64
| +--ro in-unsolicited-pkts? yang:counter64
| +--ro in-override-pkts? yang:counter64
| +--ro in-nonoverride-pkts? yang:counter64
| +--ro out-solicited-pkts? yang:counter64
| +--ro out-unsolicited-pkts? yang:counter64
| +--ro out-override-pkts? yang:counter64
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| +--ro out-nonoverride-pkts? yang:counter64
+--ro rs-stats
| +--ro in-pkts? yang:counter64
| +--ro out-pkts? yang:counter64
| +--ro drop-pkts? yang:counter64
| +--ro in-unicast-pkts? yang:counter64
| +--ro in-multicast-pkts? yang:counter64
| +--ro out-unicast-pkts? yang:counter64
| +--ro out-multicast-pkts? yang:counter64
| +--ro drop-bad-code-pkts? yang:counter64
| +--ro drop-bad-hoplimit-pkts? yang:counter64
| +--ro drop-bad-len-pkts? yang:counter64
| +--ro drop-bad-option-pkts? yang:counter64
| +--ro drop-checksum-err-pkts? yang:counter64
| +--ro drop-fragmented-pkts? yang:counter64
+--ro ra-stats
| +--ro in-pkts? yang:counter64
| +--ro out-pkts? yang:counter64
| +--ro drop-pkts? yang:counter64
| +--ro in-unicast-pkts? yang:counter64
| +--ro in-multicast-pkts? yang:counter64
| +--ro out-unicast-pkts? yang:counter64
| +--ro out-multicast-pkts? yang:counter64
| +--ro drop-bad-code-pkts? yang:counter64
| +--ro drop-bad-hoplimit-pkts? yang:counter64
| +--ro drop-bad-len-pkts? yang:counter64
| +--ro drop-bad-option-pkts? yang:counter64
| +--ro drop-checksum-err-pkts? yang:counter64
| +--ro drop-fragmented-pkts? yang:counter64
+--ro redirect-stats
+--ro in-pkts? yang:counter64
+--ro out-pkts? yang:counter64
+--ro drop-pkts? yang:counter64
+--ro drop-bad-code-pkts? yang:counter64
+--ro drop-bad-hoplimit-pkts? yang:counter64
+--ro drop-bad-len-pkts? yang:counter64
+--ro drop-bad-option-pkts? yang:counter64
+--ro drop-checksum-err-pkts? yang:counter64
+--ro drop-fragmented-pkts? yang:counter64
augment /if:interfaces/if:interface/ip:ipv6/ip:neighbor:
+--ro age? uint32
3. IPv6 Neighbor Discovery YANG Module
This section presents the YANG module of IPv6 Neighbor Discovery
defined in this document.
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This module imports modules from Common YANG Data Types [RFC9911], A
YANG Data Model for Interface Management [RFC8343], and A YANG Data
Model for IP Management [RFC8344].
<CODE BEGINS> file "ietf-ipv6-nd@2026-04-20.yang"
module ietf-ipv6-nd {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-ipv6-nd";
prefix v6nd;
import ietf-yang-types {
prefix yang;
reference
"RFC 9911: Common YANG Data Types";
}
import ietf-interfaces {
prefix if;
reference
"RFC 8343: A Yang Data Model for Interface Management";
}
import ietf-ip {
prefix ip;
reference
"RFC 8344: A Yang Data Model for IP Management";
}
organization
"IETF 6MAN (IPv6 Maintenance) Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/6man/>
WG List: 6MAN <mailto:ipv6@ietf.org>
Author: Fan Zhang
<zhangf52@chinatelecom.cn>
Author: Yongqing Zhu
<zhuyq8@chinatelecom.cn>
Author: Bo Wu
<lana.wubo@huawei.com>
Author: Jiayuan Hu
<hujy5@chinatelecom.cn>";
description
"This YANG module defines a YANG data model to configure and
manage IPv6 Neighbor Discovery (ND) and related functions,
including IPv6 address resolution, redirect, proxy Neighbor
Advertisement, Neighbor Unreachability Detection (NUD),
Duplicate Address Detection (DAD), and Enhanced DAD.
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Copyright (c) 2026 IETF Trust and the persons
identified as authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject
to the license terms contained in, the Revised BSD License
set forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(https://trustee.ietf.org/license-info).
All revisions of IETF and IANA published modules can be found
at the YANG Parameters registry group
(https://www.iana.org/assignments/yang-parameters).
This version of this YANG module is part of RFC XXXX; see
the RFC itself for full legal notices.";
// RFC Ed: replace '2026-04-20' with the module publication date
// the format is (YYYY-MM-DD)
// replace XXXX with actual RFC number and remove
// this note
revision 2026-04-20 {
description
"Initial version.";
reference
"RFC XXXX: YANG Data Model for IPv6 Neighbor Discovery";
}
/* Groupings */
grouping nd-basic-statistics {
description
"Grouping for basic statistics for IPv6 ND messages.";
leaf in-pkts {
type yang:counter64;
description
"The total number of packets received.";
}
leaf out-pkts {
type yang:counter64;
description
"The total number of packets transmitted.";
}
leaf drop-pkts {
type yang:counter64;
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description
"The total number of packets discarded.";
}
}
grouping nd-unicast-multicast-statistics {
description
"Grouping for statistics for IPv6 ND messages categorized by
unicast and multicast.";
leaf in-unicast-pkts {
type yang:counter64;
description
"The total number of packets received with the destination
address as a unicast address.";
}
leaf in-multicast-pkts {
type yang:counter64;
description
"The total number of packets received with the destination
address as a multicast address.";
}
leaf out-unicast-pkts {
type yang:counter64;
description
"The total number of packets transmitted with the destination
address as a unicast address.";
}
leaf out-multicast-pkts {
type yang:counter64;
description
"The total number of packets transmitted with the destination
address as a multicast address.";
}
}
grouping nd-drop-statistics {
description
"Grouping for statistics for IPv6 ND messages discarded by
reason.";
leaf drop-bad-code-pkts {
type yang:counter64;
description
"The total number of packets discarded due to invalid code.";
}
leaf drop-bad-hoplimit-pkts {
type yang:counter64;
description
"The total number of packets discarded due to invalid hop
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limits.";
}
leaf drop-bad-len-pkts {
type yang:counter64;
description
"The total number of packets discarded due to invalid length.";
}
leaf drop-bad-option-pkts {
type yang:counter64;
description
"The total number of packets discarded due to invalid option.";
}
leaf drop-checksum-err-pkts {
type yang:counter64;
description
"The total number of packets discarded due to checksum errors.";
}
leaf drop-fragmented-pkts {
type yang:counter64;
description
"The total number of packets discarded due to fragmentation.";
}
}
/* Data nodes */
augment "/if:interfaces/if:interface/ip:ipv6" {
description
"Augments interface configuration and state data with
parameters of IPv6 ND.";
container nd {
description
"Parameters of IPv6 ND.";
leaf reachable-time {
type uint32 {
range "1..3600000";
}
units "milliseconds";
default "30000";
description
"The time to confirm a neighbor's reachability for NUD.";
reference
"RFC4861: Neighbor Discovery for IP version 6 (IPv6)
Section 6.3.2 - BaseReachableTime";
}
leaf retrans-timer {
type uint32 {
range "1..max";
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}
units "milliseconds";
default "1000";
description
"The interval of retransmitting Neighbor Solicitations to a
neighbor for address resolution, NUD, or DAD.";
reference
"RFC4861: Neighbor Discovery for IP version 6 (IPv6)
Section 6.3.2 - RetransTimer";
}
leaf redirect {
type boolean;
default "false";
description
"Controls whether sending of ICMP Redirect messages
on the interface is enabled or disabled.
true - Sending of ICMP Redirect messages is enabled,
false - Sending of ICMP Redirect messages is disabled.";
reference
"RFC4861: Neighbor Discovery for IP version 6 (IPv6)
Section 8";
}
leaf proxy-na {
type boolean;
default "false";
description
"Controls whether proxies for one or more other nodes by
sending proxy Neighbor Advertisement.
true - Proxy NA is enabled,
false - Proxy NA is disabled.";
reference
"RFC4861: Neighbor Discovery for IP version 6 (IPv6)
Section 7.2.8";
}
container enhanced-dad {
description
"Parameters of Enhanced DAD algorithm.";
leaf enable {
type boolean;
default "false";
description
"Controls whether Enhanced DAD algorithm is enabled or
disabled.";
reference
"RFC7527: Enhanced Duplicate Address Detection
Section 4";
}
leaf auto-resolve {
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when "../enable = 'true'";
type boolean;
default "false";
description
"Controls whether the automated action is taken when
detecting duplicates. A trusted router can log a system
management message, drop the received ND message, and
block the untrusted IPv6 host nodes from which the
duplicate NS(DAD) or NA message was received.";
reference
"RFC7527: Enhanced Duplicate Address Detection
Section 5";
}
reference
"RFC7527: Enhanced Duplicate Address Detection";
}
container statistics {
config false;
description
"A collection of interface-related statistics about IPv6
ND messages.";
container ns-stats {
description
"Statistics for Neighbor Solicitation packets.";
uses nd-basic-statistics;
uses nd-unicast-multicast-statistics;
uses nd-drop-statistics;
leaf out-nud-pkts {
type yang:counter64;
description
"The total number of NS packets transmitted for NUD.";
}
}
container na-stats {
description
"Statistics for Neighbor Advertisement packets.";
uses nd-basic-statistics;
uses nd-unicast-multicast-statistics;
uses nd-drop-statistics;
leaf in-solicited-pkts {
type yang:counter64;
description
"The total number of solicited NA packets received.";
}
leaf in-unsolicited-pkts {
type yang:counter64;
description
"The total number of unsolicited NA packets received.";
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}
leaf in-override-pkts {
type yang:counter64;
description
"The total number of override NA packets received.";
}
leaf in-nonoverride-pkts {
type yang:counter64;
description
"The total number of non-override NA packets received.";
}
leaf out-solicited-pkts {
type yang:counter64;
description
"The total number of solicited NA packets transmitted.";
}
leaf out-unsolicited-pkts {
type yang:counter64;
description
"The total number of unsolicited NA packets transmitted.";
}
leaf out-override-pkts {
type yang:counter64;
description
"The total number of override NA packets transmitted.";
}
leaf out-nonoverride-pkts {
type yang:counter64;
description
"The total number of non-override NA packets
transmitted.";
}
}
container rs-stats {
description
"Statistics for Router Solicitation packets.";
uses nd-basic-statistics;
uses nd-unicast-multicast-statistics;
uses nd-drop-statistics;
}
container ra-stats {
description
"Statistics for Router Advertisement packets.";
uses nd-basic-statistics;
uses nd-unicast-multicast-statistics;
uses nd-drop-statistics;
}
container redirect-stats {
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description
"Statistics for Redirect packets.";
uses nd-basic-statistics;
uses nd-drop-statistics;
}
}
}
}
augment "/if:interfaces/if:interface/ip:ipv6/ip:neighbor" {
description
"Augments IPv6 neighbor list with parameters of IPv6 address
resolution based on IPv6 ND.";
leaf age {
when "../ip:origin = 'dynamic'";
type uint32;
units "seconds";
config false;
description
"The time that has passed since receipt of the last
reachability confirmation for the neighbor. Ignored when the
neighbor entry is static.";
reference
"RFC4861: Neighbor Discovery for IP version 6 (IPv6)
Section 7.3.3";
}
}
}
<CODE ENDS>
4. IANA Considerations
IANA is requested to register the following URI in the "ns" registry
within the "IETF XML Registry" group [RFC3688]:
URI: urn:ietf:params:xml:ns:yang:ietf-ipv6-nd
Registrant Contact: The IESG
XML: N/A; the requested URI is an XML namespace.
IANA is requested to register the following YANG module in the "YANG
Module Names" registry [RFC6020] within the "YANG Parameters"
registry group.
Name: ietf-ipv6-nd
Maintained by IANA? N
Namespace: urn:ietf:params:xml:ns:yang:ietf-ipv6-nd
Prefix: v6nd
Reference: RFC XXXX
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5. Security Considerations
This section is modeled after the template described in Section 3.7.1
of [RFC9907].
The "ietf-ipv6-nd" YANG module defines a data model that is designed
to be accessed via YANG-based management protocols, such as the
Network Configuration Protocol (NETCONF) [RFC6241] and RESTCONF
[RFC8040]. These YANG-based management protocols (1) have to use a
secure transport layer (e.g., Secure Shell (SSH) [RFC4252], TLS
[RFC9846], and QUIC [RFC9000]) and (2) have to use mutual
authentication.
The Network Configuration Access Control Model (NACM) [RFC8341]
provides the means to restrict access for particular NETCONF or
RESTCONF users to a preconfigured subset of all available NETCONF or
RESTCONF protocol operations and content.
There are a number of data nodes defined in this YANG module that are
writable/creatable/deletable (i.e., "config true", which is the
default). All writable data nodes are likely to be sensitive or
vulnerable in some network environments. Write operations (e.g.,
edit-config) and delete operations to these data nodes without proper
protection or authentication can have a negative effect on network
operations. The following subtrees and data nodes have particular
sensitivities/vulnerabilities:
* /if:interfaces/if:interface/ip:ipv6/v6nd:nd/v6nd:reachable-time
This leaf is used to consider a neighbor reachable since the last
confirmation of reachability, which could be set to big values to
prolong the effect of spoofing Neighbor Cache entries or small values
to cause unnecessary frequent NUDs.
* /if:interfaces/if:interface/ip:ipv6/v6nd:nd/v6nd:retrans-timer
This leaf is used to set the interval of retransmitting Neighbor
Solicitations, which could allow DoS attacks.
* /if:interfaces/if:interface/ip:ipv6/v6nd:nd/v6nd:redirect
This leaf is used to enable the sending of Redirect messages on an
interface, which could allow traffic to be misdirected, potentially
resulting in traffic hijacking, man-in-the-middle attacks, or DoS
attacks.
* /if:interfaces/if:interface/ip:ipv6/v6nd:nd/v6nd:proxy-na
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This leaf is used to enable proxy Neighbor Advertisement on an
interface, which could allow spoofing traffic to be injected.
Some of the readable data nodes in this YANG module may be considered
sensitive or vulnerable in some network environments. It is thus
important to control read access (e.g., via get, get-config, or
notification) to these data nodes. Specifically, the following
subtrees and data nodes have particular sensitivities/
vulnerabilities:
* /if:interfaces/if:interface/ip:ipv6/ip:neighbor/v6nd:age
Unauthorized access to this node may disclose information about IPv6
neighbor reachability and activity patterns on the network.
* /if:interfaces/if:interface/ip:ipv6/v6nd:nd/v6nd:redirect
* /if:interfaces/if:interface/ip:ipv6/v6nd:nd/v6nd:proxy-na
* /if:interfaces/if:interface/ip:ipv6/v6nd:nd/v6nd:enhanced-dad
Unauthorized access to these nodes may disclose device behavior and
security-related configuration of IPv6 Neighbor Discovery functions.
6. Acknowledgments
The authors would like to thank Bin Han, Acee Lindem, Jen Linkova,
Éric Vyncke, Changwang Lin, and many others for their helpful
comments and suggestions.
Thanks to Ebben Aries for the review and comments.
7. References
7.1. Normative References
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
DOI 10.17487/RFC4861, September 2007,
<https://www.rfc-editor.org/info/rfc4861>.
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[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862,
DOI 10.17487/RFC4862, September 2007,
<https://www.rfc-editor.org/info/rfc4862>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<https://www.rfc-editor.org/info/rfc6020>.
[RFC7527] Asati, R., Singh, H., Beebee, W., Pignataro, C., Dart, E.,
and W. George, "Enhanced Duplicate Address Detection",
RFC 7527, DOI 10.17487/RFC7527, April 2015,
<https://www.rfc-editor.org/info/rfc7527>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/info/rfc7950>.
[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration
Access Control Model", STD 91, RFC 8341,
DOI 10.17487/RFC8341, March 2018,
<https://www.rfc-editor.org/info/rfc8341>.
[RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
and R. Wilton, "Network Management Datastore Architecture
(NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
<https://www.rfc-editor.org/info/rfc8342>.
[RFC8343] Bjorklund, M., "A YANG Data Model for Interface
Management", RFC 8343, DOI 10.17487/RFC8343, March 2018,
<https://www.rfc-editor.org/info/rfc8343>.
[RFC8344] Bjorklund, M., "A YANG Data Model for IP Management",
RFC 8344, DOI 10.17487/RFC8344, March 2018,
<https://www.rfc-editor.org/info/rfc8344>.
[RFC8349] Lhotka, L., Lindem, A., and Y. Qu, "A YANG Data Model for
Routing Management (NMDA Version)", RFC 8349,
DOI 10.17487/RFC8349, March 2018,
<https://www.rfc-editor.org/info/rfc8349>.
[RFC9911] Schönwälder, J., Ed., "Common YANG Data Types", RFC 9911,
DOI 10.17487/RFC9911, December 2025,
<https://www.rfc-editor.org/info/rfc9911>.
7.2. Informative References
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[RFC4252] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH)
Authentication Protocol", RFC 4252, DOI 10.17487/RFC4252,
January 2006, <https://www.rfc-editor.org/info/rfc4252>.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/info/rfc6241>.
[RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C.
Bormann, "Neighbor Discovery Optimization for IPv6 over
Low-Power Wireless Personal Area Networks (6LoWPANs)",
RFC 6775, DOI 10.17487/RFC6775, November 2012,
<https://www.rfc-editor.org/info/rfc6775>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.
[RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
<https://www.rfc-editor.org/info/rfc8340>.
[RFC8505] Thubert, P., Ed., Nordmark, E., Chakrabarti, S., and C.
Perkins, "Registration Extensions for IPv6 over Low-Power
Wireless Personal Area Network (6LoWPAN) Neighbor
Discovery", RFC 8505, DOI 10.17487/RFC8505, November 2018,
<https://www.rfc-editor.org/info/rfc8505>.
[RFC8928] Thubert, P., Ed., Sarikaya, B., Sethi, M., and R. Struik,
"Address-Protected Neighbor Discovery for Low-Power and
Lossy Networks", RFC 8928, DOI 10.17487/RFC8928, November
2020, <https://www.rfc-editor.org/info/rfc8928>.
[RFC8981] Gont, F., Krishnan, S., Narten, T., and R. Draves,
"Temporary Address Extensions for Stateless Address
Autoconfiguration in IPv6", RFC 8981,
DOI 10.17487/RFC8981, February 2021,
<https://www.rfc-editor.org/info/rfc8981>.
[RFC9000] Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
Multiplexed and Secure Transport", RFC 9000,
DOI 10.17487/RFC9000, May 2021,
<https://www.rfc-editor.org/info/rfc9000>.
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[RFC9010] Thubert, P., Ed. and M. Richardson, "Routing for RPL
(Routing Protocol for Low-Power and Lossy Networks)
Leaves", RFC 9010, DOI 10.17487/RFC9010, April 2021,
<https://www.rfc-editor.org/info/rfc9010>.
[RFC9846] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 9846, DOI 10.17487/RFC9846, July 2026,
<https://www.rfc-editor.org/info/rfc9846>.
[RFC9907] Bierman, A., Boucadair, M., Ed., and Q. Wu, "Guidelines
for Authors and Reviewers of Documents Containing YANG
Data Models", BCP 216, RFC 9907, DOI 10.17487/RFC9907,
March 2026, <https://www.rfc-editor.org/info/rfc9907>.
[I-D.ietf-intarea-arp-yang-model]
Zheng, F., Wu, B., Wilton, R., Zhang, F., Zhu, Y., and X.
Ding, "A YANG Data Model for ARP Extensions", Work in
Progress, Internet-Draft, draft-ietf-intarea-arp-yang-
model-01, 13 April 2026,
<https://datatracker.ietf.org/doc/html/draft-ietf-intarea-
arp-yang-model-01>.
Appendix A. Example Proxy Neighbor Advertisement, Redirect, NUD, and
DAD Configuration
This example illustrates the configuration of enabling proxy Neighbor
Advertisement, Redirect, NUD, DAD, and enhanced DAD on interface eth0
with setting the "dup-addr-detect-transmits" leaf as 2, the
"reachable-time" leaf as 40000 milliseconds, and the "retrans-timer"
leaf as 2000 milliseconds, using the ietf-interfaces module
[RFC8343], the ietf-ip module [RFC8344], and the IPv6 ND module.
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<interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"
xmlns:ianaift="urn:ietf:params:xml:ns:yang:iana-if-type">
<interface>
<name>eth0</name>
<type>ianaift:ethernetCsmacd</type>
<ipv6 xmlns="urn:ietf:params:xml:ns:yang:ietf-ip">
<dup-addr-detect-transmits>2</dup-addr-detect-transmits>
<nd xmlns="urn:ietf:params:xml:ns:yang:ietf-ipv6-nd">
<reachable-time>40000</reachable-time>
<retrans-timer>2000</retrans-timer>
<redirect>true</redirect>
<proxy-na>true</proxy-na>
<enhanced-dad>
<enable>true</enable>
<auto-resolve>true</auto-resolve>
</enhanced-dad>
</nd>
</ipv6>
</interface>
</interfaces>
The following is the same example using JSON format.
{
"ietf-interfaces:interfaces": {
"interface": [
{
"name": "eth0",
"type": "iana-if-type:ethernetCsmacd",
"ietf-ip:ipv6": {
"dup-addr-detect-transmits": 2,
"ietf-ipv6-nd:nd": {
"reachable-time": 40000,
"retrans-timer": 2000,
"redirect": true,
"proxy-na": true,
"enhanced-dad": {
"enable": true,
"auto-resolve": true
}
}
}
}
]
}
}
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Appendix B. Coverage of IPv6 ND Functions in YANG Modules
This appendix summarizes the functional elements related to the IPv6
ND protocol and identifies whether they are covered by existing IETF
YANG modules or defined in this document.
The table below maps the relevant RFCs, functions or parameters, the
corresponding YANG modules, and their specific data paths. The
functions are defined in [RFC4861] (Neighbor Discovery for IP version
6 (IPv6)), [RFC4862] (IPv6 Stateless Address Autoconfiguration), and
[RFC7527] (Enhanced Duplicate Address Detection). The parameters are
defined in Section 6.2.1 and 6.3.2 of [RFC4861], Section 5.1 of
[RFC4862], and Section 3.4 of [RFC8981].
+=========+======================+==============+=================+
|RFC |Function/Parameter |Covered by |Path |
|(Section)| | | |
+=========+======================+==============+=================+
|4861 |Neighbor Cache |ietf-ip |/if:interfaces |
|s5.1 | | |/if:interface |
| | | |/ip:ipv6 |
| | | |/ip:neighbor |
+---------+----------------------+--------------+-----------------+
|4862 |Prefix List |ietf-ipv6- |/if:interfaces |
|s5.1 |(AdvPrefixList) |router- |/if:interface |
| | |advertisements|/ip:ipv6 |
| | | |/v6ur:prefix-list|
+---------+----------------------+--------------+-----------------+
|4861 |IsRouter |ietf-ip |/if:interfaces |
|s6.2.1 | | |/if:interface |
| | | |/ip:ipv6 |
| | | |/ip:forwarding |
+---------+----------------------+--------------+-----------------+
|4861 |AdvSendAdvertisements |ietf-ipv6- |/if:interfaces |
|s6.2.1 | |router- |/if:interface |
| | |advertisements|/ip:ipv6 |
| | | |/v6ur:ipv6-router|
| | | |-advertisements |
+---------+----------------------+--------------+-----------------+
|4861 |MaxRtrAdvInterval |ietf-ipv6- |/if:interfaces |
|s6.2.1 | |router- |/if:interface |
| | |advertisements|/ip:ipv6 |
| | | |/v6ur:max-rtr |
| | | |-adv-interval |
+---------+----------------------+--------------+-----------------+
|4861 |MinRtrAdvInterval |ietf-ipv6- |/if:interfaces |
|s6.2.1 | |router- |/if:interface |
| | |advertisements|/ip:ipv6 |
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| | | |/v6ur:min-rtr |
| | | |-adv-interval |
+---------+----------------------+--------------+-----------------+
|4861 |AdvManagedFlag |ietf-ipv6- |/if:interfaces |
|s6.2.1 | |router- |/if:interface |
| | |advertisements|/ip:ipv6/ |
| | | |v6ur:managed-flag|
+---------+----------------------+--------------+-----------------+
|4861 |AdvOtherConfigFlag |ietf-ipv6- |/if:interfaces |
|s6.2.1 | |router- |/if:interface |
| | |advertisements|/ip:ipv6 |
| | | |/v6ur:other- |
| | | |config-flag |
+---------+----------------------+--------------+-----------------+
|4861 |AdvLinkMTU |ietf-ipv6- |/if:interfaces |
|s6.2.1 | |router- |/if:interface |
| | |advertisements|/ip:ipv6 |
| | | |/v6ur:link-mtu |
+---------+----------------------+--------------+-----------------+
|4861 |AdvReachableTime |ietf-ipv6- |/if:interfaces |
|s6.2.1 | |router- |/if:interface |
| | |advertisements|/ip:ipv6 |
| | | |/v6ur:reachable- |
| | | |time |
+---------+----------------------+--------------+-----------------+
|4861 |AdvRetransTimer |ietf-ipv6- |/if:interfaces |
|s6.2.1 | |router- |/if:interface |
| | |advertisements|/ip:ipv6 |
| | | |/v6ur:retrans- |
| | | |timer |
+---------+----------------------+--------------+-----------------+
|4861 |AdvCurHopLimit |ietf-ipv6- |/if:interfaces |
|s6.2.1 | |router- |/if:interface |
| | |advertisements|/ip:ipv6 |
| | | |/v6ur:cur-hop- |
| | | |limit |
+---------+----------------------+--------------+-----------------+
|4861 |AdvDefaultLifetime |ietf-ipv6- |/if:interfaces |
|s6.2.1 | |router- |/if:interface |
| | |advertisements|/ip:ipv6 |
| | | |/v6ur:default- |
| | | |lifetime |
+---------+----------------------+--------------+-----------------+
|4861 |AdvPrefixList/ |ietf-ipv6- |/if:interfaces |
|s6.2.1 |AdvValidLifetime |router- |/if:interface |
| | |advertisements|/ip:ipv6 |
| | | |/v6ur:prefix-list|
| | | |/v6ur:prefix |
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| | | |/v6ur:control-adv|
| | | |-prefixes |
| | | |/v6ur:advertise |
| | | |/v6ur:valid |
| | | |-lifetime |
+---------+----------------------+--------------+-----------------+
|4861 |AdvPrefixList/ |ietf-ipv6- |/if:interfaces |
|s6.2.1 |AdvOnLinkFlag |router- |/if:interface |
| | |advertisements|/ip:ipv6 |
| | | |/v6ur:prefix-list|
| | | |/v6ur:prefix |
| | | |/v6ur:control-adv|
| | | |-prefixes |
| | | |/v6ur:advertise/ |
| | | |v6ur:on-link-flag|
+---------+----------------------+--------------+-----------------+
|4861 |AdvPrefixList/ |ietf-ipv6- |/if:interfaces |
|s6.2.1 |AdvPreferredLifetime |router- |/if:interface |
| | |advertisements|/ip:ipv6 |
| | | |/v6ur:prefix-list|
| | | |/v6ur:prefix |
| | | |/v6ur:control-adv|
| | | |-prefixes |
| | | |/v6ur:advertise |
| | | |/v6ur:preferred |
| | | |-lifetime |
+---------+----------------------+--------------+-----------------+
|4861 |AdvPrefixList/ |ietf-ipv6- |/if:interfaces |
|s6.2.1 |AdvAutonomousFlag |router- |/if:interface |
| | |advertisements|/ip:ipv6 |
| | | |/v6ur:prefix-list|
| | | |/v6ur:prefix |
| | | |/v6ur:control-adv|
| | | |-prefixes |
| | | |/v6ur:advertise |
| | | |/v6ur:autonomous |
| | | |-flag |
+---------+----------------------+--------------+-----------------+
|4861 |LinkMTU |- |- |
|s6.3.2 | | | |
+---------+----------------------+--------------+-----------------+
|4861 |CurHopLimit |- |- |
|s6.3.2 | | | |
+---------+----------------------+--------------+-----------------+
|4861 |BaseReachableTime |ietf-ipv6-nd |/if:interfaces |
|s6.3.2 | | |/if:interface |
| | | |/ip:ipv6/v6nd:nd |
| | | |/v6nd:reachable |
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| | | |-time |
+---------+----------------------+--------------+-----------------+
|4861 |ReachableTime |- |- |
|s6.3.2 | | | |
+---------+----------------------+--------------+-----------------+
|4861 |RetransTimer |ietf-ipv6-nd |/if:interfaces |
|s6.3.2 | | |/if:interface |
|/4862 | | |/ip:ipv6/v6nd:nd |
|s5.1 | | |/v6nd:retrans |
| | | |-timer |
+---------+----------------------+--------------+-----------------+
|4861 |Proxy Neighbor |ietf-ipv6-nd |/if:interfaces |
|s7.2.8 |Advertisements | |/if:interface |
| | | |/ip:ipv6/v6nd:nd |
| | | |/v6nd:proxy-na |
+---------+----------------------+--------------+-----------------+
|4861 |Redirect |ietf-ipv6-nd |/if:interfaces |
|s8 | | |/if:interface |
| | | |/ip:ipv6/v6nd:nd |
| | | |/v6nd:redirect |
+---------+----------------------+--------------+-----------------+
|4862 |DupAddrDetectTransmits|ietf-ip |/if:interfaces |
|s5.1 | | |/if:interface |
| | | |/ip:ipv6/ip:dup |
| | | |-addr-detect |
| | | |-transmits |
+---------+----------------------+--------------+-----------------+
|4862 |Creation of Global |ietf-ip |/if:interfaces |
|s5.5 |Addresses | |/if:interface |
| | | |/ip:ipv6 |
| | | |/ip:autoconf |
| | | |/ip:create- |
| | | |global- |
| | | |addresses |
+---------+----------------------+--------------+-----------------+
|8981 |Creation of Temporary |ietf-ip |/if:interfaces |
|s3.4 |Addresses | |/if:interface |
| | | |/ip:ipv6 |
| | | |/ip:autoconf |
| | | |/ip:create- |
| | | |temporary- |
| | | |addresses |
+---------+----------------------+--------------+-----------------+
|8981 |TEMP_VALID_LIFETIME |ietf-ip |/if:interfaces |
|s3.4 | | |/if:interface |
| | | |/ip:ipv6 |
| | | |/ip:autoconf |
| | | |/ip:temporary- |
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| | | |valid-lifetime |
+---------+----------------------+--------------+-----------------+
|8981 |TEMP_PREFERRED_ |ietf-ip |/if:interfaces |
|s3.4 |LIFETIME | |/if:interface |
| | | |/ip:ipv6 |
| | | |/ip:autoconf |
| | | |/ip:temporary- |
| | | |preferred- |
| | | |lifetime |
+---------+----------------------+--------------+-----------------+
|7527 |Enhanced Duplicate |ietf-ipv6-nd |/if:interfaces |
|s4 |Address Detection | |/if:interface |
| | | |/ip:ipv6/v6nd:nd/|
| | | |v6nd:enhanced-dad|
+---------+----------------------+--------------+-----------------+
|7527 |Automated Resolving |ietf-ipv6-nd |/if:interfaces |
|s5 |of Duplicates | |/if:interface |
| | | |/ip:ipv6/v6nd:nd/|
| | | |v6nd:auto-resolve|
+---------+----------------------+--------------+-----------------+
Table 1: Coverage of IPv6 ND Functions in YANG Modules
Contributors
Bin Han
Huawei
China
Email: hanbin3@huawei.com
Authors' Addresses
Fan Zhang
China Telecom
Guangzhou
China
Email: zhangf52@chinatelecom.cn
Yongqing Zhu
China Telecom
Guangzhou
China
Email: zhuyq8@chinatelecom.cn
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Bo Wu
Huawei
China
Email: lana.wubo@huawei.com
Jiayuan Hu
China Telecom
Guangzhou
China
Email: hujy5@chinatelecom.cn
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