IPv6 术语表 Glossary
本页收录配置和排障 IPv6 时最常见的术语，按主题分类，中英双语对照。配置实战请参考 Photoincat 2 IPv6 PPPoE 与 Photonicat IPv6 Native, NAT6模式。
This page collects the most common IPv6 jargon for configuration and troubleshooting, sorted by topic, bilingual (Chinese / English). For hands-on setup see Photoincat 2 IPv6 PPPoE and Photonicat IPv6 Native, NAT6模式.
一、基础概念 Basics
| 术语 Term | 中文说明 | English |
|---|---|---|
| IPv6 | 第 6 版互联网协议，128 位地址（约 3.4×10³⁸ 个），解决 IPv4 地址枯竭问题，原生支持自动配置与端到端直连。 | Internet Protocol version 6, with 128-bit addresses (~3.4×10³⁸), solving IPv4 exhaustion; natively supports autoconfiguration and end-to-end connectivity. |
| IPv4 | 第 4 版互联网协议，32 位地址（约 43 亿个），已枯竭，普遍依赖 NAT 共享公网地址。 | Internet Protocol version 4, 32-bit addresses (~4.3 billion), exhausted; commonly shared behind NAT. |
| 双栈 Dual Stack | 设备/网络同时运行 IPv4 和 IPv6，两套协议并行、互不依赖，是目前最主流的过渡方式。 | Running IPv4 and IPv6 simultaneously and independently on the same device/network; the most common transition strategy today. |
| 地址格式 Address Format | 8 组 16 位十六进制数，冒号分隔，如 240e:38c:8449:2200::1。前导零可省略；连续全零组可用 :: 压缩一次；%eth0 表示链路本地地址的出口接口（Zone ID）。 |
Eight groups of 16-bit hex separated by colons, e.g. 240e:38c:8449:2200::1. Leading zeros may be dropped; one run of zero groups can be compressed to ::; %eth0 is a zone ID selecting the interface for link-local addresses.
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| 前缀 Prefix | 地址的高位网络部分，写作 地址/长度，如 240e:38c:8449:2200::/56。类似 IPv4 的 CIDR。 |
The high-order network part of an address, written address/length, e.g. 240e:38c:8449:2200::/56; analogous to IPv4 CIDR.
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| /64 | IPv6 局域网子网的标准大小。SLAAC 只能工作在 /64 上；运营商委托的 /56、/60 会被路由器切分成若干 /64 分给各内网接口。 | The standard IPv6 LAN subnet size. SLAAC only works on /64; an ISP-delegated /56 or /60 is split by the router into multiple /64s for LAN interfaces. |
| 接口标识符 IID (Interface Identifier) | 地址的低 64 位，标识子网内的具体接口，可由 EUI-64、随机数或 DHCPv6 生成。 | The low 64 bits of an address identifying an interface within the subnet; generated via EUI-64, randomization, or DHCPv6. |
| EUI-64 | 由网卡 48 位 MAC 地址扩展生成 64 位 IID 的方法（中间插入 ff:fe 并翻转 U/L 位），如 MAC bc:24:11:75:97:aa → be24:11ff:fe75:97aa。会暴露硬件信息，故有隐私地址扩展。 |
Deriving a 64-bit IID from the 48-bit MAC (insert ff:fe, flip the U/L bit), e.g. MAC bc:24:11:75:97:aa → be24:11ff:fe75:97aa. Leaks hardware identity, hence privacy extensions.
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| 作用域 Scope | 地址的有效范围：链路本地（link-local）、唯一本地（ULA）、全球（global）。不同作用域地址不可互相路由。 | The reach of an address: link-local, unique-local (ULA), or global. Addresses of different scopes are not interchangeable for routing. |
| Hop Limit | IPv6 头部字段，等价于 IPv4 的 TTL，每经过一跳减 1，为 0 时丢弃。 | IPv6 header field equivalent to IPv4 TTL; decremented per hop, packet dropped at 0. |
| MTU | 链路最大传输单元。IPv6 最小要求 1280 字节；PPPoE 线路常见 1492。IPv6 路由器不做分片，全靠 PMTUD。 | Maximum Transmission Unit. IPv6 requires ≥1280 bytes; PPPoE links are typically 1492. IPv6 routers never fragment — path MTU discovery is mandatory. |
二、地址类型 Address Types
| 术语 Term | 中文说明 | English |
|---|---|---|
| GUA (Global Unicast Address) | 全球单播地址（2000::/3，如 240e:、2408:、2409: 开头），公网可路由，即"全球直连"地址。 |
Globally routable unicast address (2000::/3, e.g. prefixes 240e:, 2408:, 2409:) — the "directly reachable from the internet" address.
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| ULA (Unique Local Address) | 唯一本地地址（fc00::/7，实际使用 fd00::/8），类似 IPv4 私网地址，仅内网有效，不被公网路由。OpenWrt 默认自动生成一个 fd 前缀。 |
Unique Local Address (fc00::/7, in practice fd00::/8) — like RFC1918 private space; LAN-only, never routed on the internet. OpenWrt auto-generates one fd prefix by default.
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| LLA (Link-Local Address) | 链路本地地址（fe80::/10），每个 IPv6 接口必有，仅本链路有效，用于邻居发现、路由协商；IPv6 默认网关通常就是路由器的 fe80 地址。 |
Link-local address (fe80::/10); mandatory on every IPv6 interface, valid only on-link, used for NDP and routing. The IPv6 default gateway is usually the router's fe80 address.
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| 组播 Multicast | ff00::/8，一对多通信。IPv6 没有广播，全部用组播替代，如 ff02::1（本链路所有节点）、ff02::2（所有路由器）。 |
ff00::/8, one-to-many. IPv6 has no broadcast — multicast replaces it, e.g. ff02::1 (all nodes on link), ff02::2 (all routers).
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| 任播 Anycast | 同一地址配置在多个节点上，路由把流量送到"最近"的一个，常用于 DNS、CDN。 | The same address on multiple nodes; routing delivers to the "nearest" one. Common for DNS and CDNs. |
| 环回地址 Loopback (::1) | 等价于 IPv4 的 127.0.0.1，仅本机有效。 | Equivalent of 127.0.0.1; host-internal only. |
| 未指定地址 Unspecified (::) | 全零地址，表示"尚无地址"，如 DAD 探测时的源地址；也用于表示默认路由 ::/0。 |
The all-zeros address meaning "no address yet" (e.g. source during DAD); ::/0 also denotes the default route.
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| 被请求节点组播 Solicited-Node Multicast | ff02::1:ffXX:XXXX，由单播地址末 24 位生成，邻居发现（解析 MAC）时用它替代广播，效率更高。 |
ff02::1:ffXX:XXXX, derived from the last 24 bits of a unicast address; used by NDP for address resolution instead of broadcast.
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| 隐私地址 Privacy / Temporary Address (RFC 4941) | 随机生成、定期更换的 SLAAC 地址，用作出站连接的源地址，避免通过固定 IID 被长期跟踪。 | Randomized, periodically rotated SLAAC addresses used as source for outbound connections, preventing tracking via a stable IID. |
| 稳定隐私地址 Stable Privacy (RFC 7217) | 不暴露 MAC 但在同一网络内保持稳定的 IID 生成方式（按前缀+密钥哈希），兼顾隐私与可管理性，现代系统默认采用。 | Opaque, per-network-stable IIDs (hash of prefix+secret) that hide the MAC yet stay constant on a given network; the modern OS default. |
| 弃用地址 Deprecated Address | preferred lifetime 已过期但 valid lifetime 未到的地址：现有连接可继续用，新连接不再选它作源地址。前缀更换时常见。 | An address past its preferred lifetime but still valid: existing sessions continue, new connections stop selecting it as source. Common during prefix changes. |
| 生存期 Lifetimes (valid / preferred) | RA/DHCPv6 为每个地址/前缀附带两个倒计时：preferred（优先使用期）与 valid（有效期）。动态前缀的地址会显示剩余秒数而非 forever。 | Every RA/DHCPv6 address or prefix carries two timers: preferred and valid lifetime. Dynamic-prefix addresses show a countdown instead of "forever". |
三、地址获取与分配 Address Acquisition
| 术语 Term | 中文说明 | English |
|---|---|---|
| SLAAC (Stateless Address Autoconfiguration) | 无状态地址自动配置：主机收到路由器 RA 中带 A 标志的 /64 前缀后，自己拼出完整地址（前缀+IID），无需服务器记录状态。最常用的 IPv6 分配方式，Android 只支持 SLAAC。 | Stateless autoconfiguration: a host combines an RA-advertised /64 prefix (with the A flag) with its own IID to form an address — no server keeps state. The most common IPv6 method; Android supports only SLAAC. |
| DHCPv6 (Stateful) | 有状态地址分配：服务器（如 odhcpd）记录并下发具体 /128 地址与 DNS 等信息，便于集中管理和固定地址。 | Stateful assignment: a server (e.g. odhcpd) leases specific /128 addresses plus options like DNS, enabling central management and static leases. |
| 无状态 DHCPv6 (Stateless DHCPv6) | 地址由 SLAAC 生成，仅通过 DHCPv6 获取 DNS 等附加信息（对应 RA 的 O 标志）。 | Addresses come from SLAAC; DHCPv6 only supplies extra options such as DNS (signaled by the RA O flag). |
| PD (Prefix Delegation, 前缀委托) | 运营商通过 DHCPv6-PD 把一整段前缀（常见 /56、/60）委托给你的路由器，路由器再切成 /64 分给各内网接口。这是内网获得公网 IPv6 的关键机制。 | The ISP delegates a whole prefix (typically /56 or /60) to your router via DHCPv6-PD; the router splits it into /64s for LAN interfaces. This is how the LAN gets global IPv6. |
| RA (Router Advertisement) | 路由器周期性（或应 RS 请求）组播的 ICMPv6 通告，携带前缀、默认网关生存期、M/O/A 标志、DNS 等，是 SLAAC 的载体。 | ICMPv6 announcements a router multicasts periodically (or in reply to an RS), carrying prefixes, router lifetime, M/O/A flags, DNS, etc.; the vehicle of SLAAC. |
| RS (Router Solicitation) | 主机上线时主动发出的"请路由器立刻发 RA"的请求（发往 ff02::2）。 | A host's "please send an RA now" request (to ff02::2) when it comes up. |
| M 标志 (Managed flag) | RA 中的标志位：建议客户端用有状态 DHCPv6 获取地址。 | RA flag telling clients to obtain addresses via stateful DHCPv6. |
| O 标志 (Other-config flag) | RA 标志位：地址用 SLAAC，但 DNS 等其他配置去问 DHCPv6。 | RA flag: addresses via SLAAC, but fetch other options (DNS etc.) from DHCPv6. |
| A 标志 (Autonomous flag) | RA 前缀选项里的标志位：允许主机用该前缀做 SLAAC。没有 A 标志就没有 SLAAC。 | Per-prefix RA flag permitting SLAAC with that prefix. No A flag, no SLAAC. |
| L 标志 (On-link flag) | RA 前缀选项标志位：该前缀在本链路直达，同前缀主机间直接通信、不经路由器。 | Per-prefix RA flag declaring the prefix on-link, so same-prefix hosts talk directly without the router. |
| Router Lifetime | RA 中宣告"我可当默认网关"的有效期；设为 0 表示"我发前缀/DNS 但别把我当默认网关"。多路由环境排障关键参数。 | How long the sender may serve as default gateway; 0 means "use my prefixes/DNS but not me as gateway". Key knob in multi-router LANs. |
| 路由器优先级 Router Preference (RFC 4191) | RA 中的 high/medium/low 优先级，让客户端在多个网关间选优。OpenWrt 对应 ra_preference。 |
The high/medium/low preference in RAs guiding clients among multiple gateways; ra_preference in OpenWrt.
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| RDNSS / DNSSL | RA 直接携带的 DNS 服务器地址（RDNSS）与 DNS 搜索域（DNSSL），使纯 SLAAC 环境无需 DHCPv6 也能拿到 DNS。 | DNS server addresses (RDNSS) and search domains (DNSSL) carried directly in RAs, so pure-SLAAC hosts get DNS without DHCPv6. |
| DUID (DHCP Unique Identifier) | DHCPv6 客户端/服务器的唯一标识（替代 IPv4 时代的 MAC），做 IPv6 静态租约时要绑定 DUID 而不是 MAC。 | The unique identifier of DHCPv6 endpoints (replacing MAC from the IPv4 era); IPv6 static leases bind to DUID, not MAC. |
| IA_NA / IA_PD | DHCPv6 请求中的两类"身份关联"：IA_NA 要一个普通地址（/128），IA_PD 要一段委托前缀。路由器 WAN 口两者都会请求。 | The two DHCPv6 identity associations: IA_NA requests a normal /128 address, IA_PD requests a delegated prefix. A router WAN requests both. |
| 源地址选择 Source Address Selection (RFC 6724) | 主机有多个地址时选哪个作源地址的规则（作用域匹配、标签匹配、最长前缀匹配等）。多运营商前缀共存时，选错源会被上游按源过滤丢包。 | The rule set (scope match, label match, longest prefix match…) picking a source among multiple addresses. With multiple ISP prefixes, a wrong source gets dropped by upstream source filtering. |
| 地址标签 Address Label | RFC 6724 策略表中的标签，可人为调整（如 ip addrlabel / networkd [IPv6AddressLabel]）来控制源地址选择倾向。 |
Labels in the RFC 6724 policy table, tunable (via ip addrlabel or networkd [IPv6AddressLabel]) to steer source selection.
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四、邻居发现与协议机制 NDP & Protocol Mechanics
| 术语 Term | 中文说明 | English |
|---|---|---|
| ICMPv6 | IPv6 的控制协议，承载差错报告、Ping、邻居发现、MLD 等。防火墙不能一刀切禁 ICMPv6，否则 NDP/PMTUD 全部失效。 | IPv6's control protocol: errors, ping, NDP, MLD. Never blanket-block ICMPv6 — NDP and PMTUD break. |
| NDP (Neighbor Discovery Protocol) | 邻居发现协议，基于 ICMPv6，替代 IPv4 的 ARP + DHCP 发现 + ICMP 重定向：地址解析、路由器发现、重复检测、不可达检测都靠它。 | The ICMPv6-based protocol replacing ARP, DHCP discovery and redirects: address resolution, router discovery, DAD, and reachability detection. |
| NS / NA (Neighbor Solicitation / Advertisement) | 邻居请求/通告，等价于 ARP 的请求/应答，把 IPv6 地址解析为 MAC。 | The IPv6 equivalents of ARP request/reply, resolving IPv6 addresses to MACs. |
| DAD (Duplicate Address Detection) | 重复地址检测：地址启用前先发 NS 探测有没有人已占用，防止冲突。 | Probing (via NS) that a tentative address is unused before enabling it. |
| NUD (Neighbor Unreachability Detection) | 邻居不可达检测：持续验证邻居（含默认网关）是否仍然可达，不可达时切换路由。ip -6 neigh 里的 REACHABLE/STALE 状态即由它维护。 |
Continuously verifying neighbors (incl. gateways) are still reachable, switching routes when not. Maintains the REACHABLE/STALE states seen in ip -6 neigh.
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| MLD (Multicast Listener Discovery) | 组播侦听发现（ICMPv6 版 IGMP），交换机/路由器据此裁剪组播转发。NDP 依赖组播，故桥接设备错误过滤 MLD 会导致 IPv6 玄学故障。 | The ICMPv6 counterpart of IGMP for pruning multicast. NDP relies on multicast, so bridges mis-filtering MLD cause mysterious IPv6 failures. |
| NDP 代理 NDP Proxy (ndppd / ndp relay) | 路由器代替下游设备应答 NS，让上游以为这些地址在本链路，用于旁路由/中继/没有 PD 的场景（OpenWrt ndp: relay）。 |
The router answers NS on behalf of downstream hosts so upstream believes they're on-link; used for bridged/relay setups without PD (OpenWrt ndp: relay).
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| PMTUD (Path MTU Discovery) | 路径 MTU 发现：IPv6 路由器不分片，靠 ICMPv6 "Packet Too Big" 让源端减小包长。被防火墙误杀时表现为小包通、大包（网页/下载）挂。 | IPv6 routers don't fragment; ICMPv6 "Packet Too Big" tells the sender to shrink packets. When firewalled away: pings work, big transfers hang. |
| ECMP (Equal-Cost Multi-Path) | 等价多路径：多个同优先级默认路由按流哈希分担。多路由器 LAN 中若某网关无 IPv6 上行，会出现"部分连接黑洞"式间歇故障。 | Flow-hashed load sharing across equal default routes. In multi-router LANs a gateway without IPv6 upstream causes intermittent per-flow blackholes. |
五、过渡与转换技术 Transition & Translation
| 术语 Term | 中文说明 | English |
|---|---|---|
| NAT6 / NAT66 | 对 IPv6 做源地址转换：内网用 ULA，出口伪装成路由器的 GUA。牺牲了端到端直连，仅建议在运营商不给 PD 前缀时使用。参见 Photonicat IPv6 Native, NAT6模式。 | Source-NAT for IPv6: LAN uses ULA, egress masqueraded to the router's GUA. Sacrifices end-to-end reachability; only recommended when the ISP delegates no prefix. See Photonicat IPv6 Native, NAT6模式. |
| NPTv6 (Network Prefix Translation) | 无状态 1:1 前缀替换（RFC 6296），内外前缀一一映射，比 NAT66 干净，常用于多线/前缀变化场景。 | Stateless 1:1 prefix rewriting (RFC 6296); cleaner than NAT66, used for multihoming or unstable prefixes. |
| NAT64 | 让纯 IPv6 网络访问 IPv4 互联网的协议转换器，把 64:ff9b::/96 内嵌的 IPv4 地址翻译成真实 IPv4 流量。 |
Translates IPv6-only clients to the IPv4 internet by mapping IPv4 addresses embedded in 64:ff9b::/96.
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| DNS64 | 与 NAT64 配套的 DNS：目标只有 A 记录时合成假 AAAA（指向 NAT64 前缀），引导纯 IPv6 客户端走 NAT64。 | Companion to NAT64: synthesizes AAAA records (pointing into the NAT64 prefix) for IPv4-only destinations. |
| 464XLAT | 移动网络主流方案：终端侧 CLAT + 运营商侧 NAT64/PLAT，让纯 IPv6 蜂窝网上的 IPv4-only 应用也能工作。 | The mobile-network staple: client-side CLAT plus provider-side NAT64 (PLAT), letting IPv4-only apps work over IPv6-only cellular. |
| DS-Lite (Dual-Stack Lite) | 运营商只给 IPv6，IPv4 流量封装进 IPv6 隧道送到运营商侧 CGN 统一做 NAT。 | ISP provides only IPv6; IPv4 is tunneled over IPv6 to a carrier-grade NAT. |
| 6in4 / SIT 隧道 | 把 IPv6 包封装在 IPv4 协议 41 里的静态隧道，如 HE tunnelbroker，常用于运营商无 IPv6 时体验 IPv6。 | Static IPv6-in-IPv4 (protocol 41) tunnels, e.g. HE tunnelbroker; a way to get IPv6 when the ISP offers none. |
| 6to4 / 6rd | 由 IPv4 地址自动派生 IPv6 前缀的隧道技术：6to4（2002::/16，已淘汰）和运营商可控的改进版 6rd。 | Tunnels deriving IPv6 prefixes from IPv4 addresses: legacy 6to4 (2002::/16, deprecated) and its ISP-managed successor 6rd. |
| Teredo | 穿越 NAT 的 IPv6-over-UDP 隧道（2001::/32），Windows 曾内置，现基本淘汰。 | IPv6-over-UDP tunneling through NAT (2001::/32); once built into Windows, now essentially retired. |
| MAP-E / MAP-T | 无状态的运营商级 IPv4-over-IPv6 方案，按规则把 IPv4 地址+端口段映射进 IPv6 前缀（封装 E / 翻译 T）。 | Stateless carrier-grade IPv4-over-IPv6: rule-based mapping of IPv4 address+port ranges into IPv6 prefixes (Encapsulation / Translation). |
| CGN / CGNAT | 运营商级 NAT，多个用户共享一个公网 IPv4。IPv6 的普及正是为了摆脱它。 | Carrier-Grade NAT sharing one public IPv4 among many subscribers — exactly what IPv6 adoption avoids. |
六、OpenWrt / photonicat 相关 OpenWrt & photonicat Specifics
| 术语 Term | 中文说明 | English |
|---|---|---|
| odhcpd | OpenWrt 的 RA / DHCPv6 / NDP 代理服务端，向 LAN 下发前缀和地址；LuCI 里 LAN 的 "DHCPv6/RA 服务" 就是它。 | OpenWrt's RA/DHCPv6/NDP-proxy server distributing prefixes and addresses to the LAN; the "DHCPv6/RA service" settings in LuCI drive it. |
| odhcp6c | OpenWrt 的 WAN 侧 DHCPv6 客户端，负责向运营商请求 IA_NA 地址和 IA_PD 前缀。 | OpenWrt's WAN-side DHCPv6 client requesting IA_NA addresses and IA_PD prefixes from the ISP. |
| wan_6 (动态别名接口) | WAN 设为 ipv6='auto' 时，netifd 在 PPPoE/DHCP 逻辑口上自动创建的 IPv6 虚拟接口（注意下划线，区别于手工建的 wan6），负责 DHCPv6/PD。26.04 固件无需手工创建 wan6。 |
The dynamic IPv6 alias interface netifd spawns on the PPPoE/DHCP link when WAN has ipv6='auto' (underscore — distinct from a manual wan6). Handles DHCPv6/PD; no manual wan6 needed on 26.04 firmware.
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| ip6assign | LAN 接口选项：从委托前缀中给该接口分配多长的子网（通常 60 或 64）。不设则 LAN 拿不到公网前缀。 | LAN option: the subnet length assigned to this interface from the delegated pool (usually 60 or 64). Unset = LAN never gets a global prefix. |
| ip6class (IPv6 前缀过滤器) | 限制接口只接受某类前缀（如 local=ULA、wan_6）。最常见故障源：被设成 local 后内网只有 fd 地址、无公网 IPv6。一般应留空。 | Restricts which prefix classes an interface accepts (e.g. local=ULA, wan_6). Top failure cause: set to "local" the LAN only gets fd addresses and no global IPv6. Normally leave empty. |
| ip6hint | 指定接口从委托前缀中取哪个 /64 子网的十六进制序号，便于固定各 VLAN 的子网编号。 | Hex hint choosing which /64 out of the delegation an interface takes; handy for stable per-VLAN subnet numbering. |
| ula_prefix (network.globals) | OpenWrt 全局自动生成的 ULA 前缀（fd 开头），保证公网前缀变化/断线时内网 IPv6 互访依然稳定。 | The auto-generated global ULA prefix (fd…) keeping LAN-internal IPv6 stable even when the ISP prefix changes or the WAN drops. |
| 混合模式 Hybrid mode | LuCI 中 RA/DHCPv6/NDP 的 "hybrid"：有委托前缀时当服务器，配置了中继上游时当中继，自动切换，日常建议选它。 | LuCI's "hybrid" for RA/DHCPv6/NDP: acts as server when holding a delegated prefix, as relay when an upstream master is set. The sensible default. |
| fw4 / nftables | OpenWrt 22.03 起的防火墙（基于 nftables），IPv4/IPv6 统一规则。默认放行 lan→wan 转发与必要 ICMPv6，IPv6 上网无需加规则。 | OpenWrt's firewall since 22.03 (nftables-based) with unified v4/v6 rules. Allows lan→wan forwarding and essential ICMPv6 by default — no extra rules needed for outbound IPv6. |
| Docker ip6tables 坑 (Docker ip6tables pitfall) | Docker 27+ 默认接管 ip6tables，创建 policy drop 的 ip6 filter FORWARD 链，丢掉所有转发的 IPv6（fw4 放行也没用）。修复见 Photoincat 2 IPv6 PPPoE 第 4 节。 |
Docker 27+ manages ip6tables by default, creating an ip6 filter FORWARD chain with policy drop that kills all forwarded IPv6 regardless of fw4. Fix in Photoincat 2 IPv6 PPPoE §4.
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| 源限定默认路由 Source-restricted default route | OpenWrt 安装的 IPv6 默认路由形如 default from 240e:xxxx::/56 via …，只转发源地址属于本运营商前缀的流量，防止源地址伪造/多线源错配。 |
OpenWrt installs IPv6 defaults like default from 240e:xxxx::/56 via …, forwarding only traffic sourced from that ISP's prefix — anti-spoofing, and a gotcha in multihomed LANs.
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| sourcefilter | OpenWrt DHCPv6 接口选项，设 0 可关闭上述按源过滤（放宽多线场景限制）。 | OpenWrt DHCPv6 interface option; 0 disables the source filtering above (loosens multihoming). |
七、DNS 与诊断 DNS & Diagnostics
| 术语 Term | 中文说明 | English |
|---|---|---|
| AAAA 记录 | 域名到 IPv6 地址的 DNS 记录（A 记录的 IPv6 版）。nslookup -type=AAAA photonicat.com 可查询。 |
The DNS record mapping a name to an IPv6 address (IPv6 counterpart of A). Query with nslookup -type=AAAA photonicat.com.
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| Happy Eyeballs (RFC 8305) | 双栈主机同时尝试 IPv6 和 IPv4 连接、择快而用的算法，避免一边故障导致网页卡顿。也因此 IPv6 半瘫时症状常是"偶尔慢"而非"全断"。 | Dual-stack hosts race IPv6 vs IPv4 and use the faster; broken IPv6 thus shows up as "sometimes slow", not "fully down". |
| ping -6 / ping6 | IPv6 连通性测试，如 ping -6 photonicat.com；链路本地地址要带接口：ping fe80::1%br-lan。 |
IPv6 reachability test, e.g. ping -6 photonicat.com; link-local targets need a zone: ping fe80::1%br-lan.
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| traceroute6 / mtr | 逐跳追踪 IPv6 路径，定位断在内网、运营商还是远端。 | Hop-by-hop IPv6 path tracing to locate whether failures are local, ISP-side, or remote. |
| ip -6 addr / ip -6 route / ip -6 neigh | Linux 查看 IPv6 地址、路由表（注意 default via fe80::…）和邻居表（等价 ARP 表）的三板斧。 |
The Linux trio for inspecting addresses, routes (note default via fe80::…) and the neighbor (ARP-equivalent) table.
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| ifstatus | OpenWrt 查询接口运行状态的命令：ifstatus wan_6 看运营商给的地址/前缀，ifstatus lan 看前缀是否分到内网。 |
OpenWrt's interface state tool: ifstatus wan_6 shows ISP-issued address/prefix, ifstatus lan shows whether it reached the LAN.
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| RA 抓包 (tcpdump) | tcpdump -i br-lan -vv 'icmp6 and ip6[40]==134' 直接看 RA 的前缀和标志位，是排查 SLAAC 的终极手段。 |
tcpdump -i br-lan -vv 'icmp6 and ip6[40]==134' shows RA prefixes and flags on the wire — the definitive SLAAC debugging tool.
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| test-ipv6.com | 浏览器端一键检测 IPv6 连通性和评分的网站（国内亦可用 testipv6.cn）。 | Browser-based one-click IPv6 connectivity scoring (testipv6.cn inside China). |