保留 IP 地址段
根据 IANA 特殊用途登记列出不属于普通公网地址的地址块，并提供检查工具，告诉你某个地址属于哪一个。
100.64.12.7 属于 100.64.0.0/10：共享地址空间（CGNAT）。
IPv4 特殊用途地址块
| 地址块 | 用途 | 定义于 | 可从互联网访问 |
|---|---|---|---|
| 0.0.0.0/8 | 未指定This network | RFC 791 | 否 |
| 10.0.0.0/8 | 私有网络Private-Use | RFC 1918 | 否 |
| 100.64.0.0/10 | 共享地址空间（CGNAT）Shared Address Space (CGNAT) | RFC 6598 | 否 |
| 127.0.0.0/8 | 环回Loopback | RFC 1122 | 否 |
| 169.254.0.0/16 | 链路本地Link-Local | RFC 3927 | 否 |
| 172.16.0.0/12 | 私有网络Private-Use | RFC 1918 | 否 |
| 192.0.0.0/24 | 协议分配IETF Protocol Assignments | RFC 6890 | 否 |
| 192.0.2.0/24 | 文档用途Documentation (TEST-NET-1) | RFC 5737 | 否 |
| 192.31.196.0/24 | 任播AS112-v4 | RFC 7535 | 是 |
| 192.52.193.0/24 | 协议分配AMT | RFC 7450 | 是 |
| 192.88.99.0/24 | 保留Deprecated 6to4 Relay Anycast | RFC 7526 | 否 |
| 192.168.0.0/16 | 私有网络Private-Use | RFC 1918 | 否 |
| 192.175.48.0/24 | 任播Direct Delegation AS112 Service | RFC 7534 | 是 |
| 198.18.0.0/15 | 基准测试Benchmarking | RFC 2544 | 否 |
| 198.51.100.0/24 | 文档用途Documentation (TEST-NET-2) | RFC 5737 | 否 |
| 203.0.113.0/24 | 文档用途Documentation (TEST-NET-3) | RFC 5737 | 否 |
| 224.0.0.0/4 | 组播Multicast | RFC 5771 | 否 |
| 240.0.0.0/4 | 保留Reserved for future use | RFC 1112 | 否 |
| 255.255.255.255/32 | 广播Limited Broadcast | RFC 919 | 否 |
IPv6 特殊用途地址块
| 地址块 | 用途 | 定义于 | 可从互联网访问 |
|---|---|---|---|
| ::/128 | 未指定Unspecified Address | RFC 4291 | 否 |
| ::1/128 | 环回Loopback Address | RFC 4291 | 否 |
| ::ffff:0:0/96 | 地址转换IPv4-mapped Address | RFC 4291 | 否 |
| 64:ff9b::/96 | 地址转换IPv4-IPv6 Translation (NAT64) | RFC 6052 | 是 |
| 64:ff9b:1::/48 | 地址转换Local-use IPv4/IPv6 Translation | RFC 8215 | 否 |
| 100::/64 | 保留Discard-Only Address Block | RFC 6666 | 否 |
| 2001::/32 | 地址转换TEREDO | RFC 4380 | 否 |
| 2001:2::/48 | 基准测试Benchmarking | RFC 5180 | 否 |
| 2001:db8::/32 | 文档用途Documentation | RFC 3849 | 否 |
| 2001:10::/28 | 保留Deprecated (ORCHID) | RFC 4843 | 否 |
| 2001:20::/28 | 协议分配ORCHIDv2 | RFC 7343 | 是 |
| 2002::/16 | 地址转换6to4 | RFC 3056 | 否 |
| 3fff::/20 | 文档用途Documentation | RFC 9637 | 否 |
| 5f00::/16 | 协议分配Segment Routing (SRv6) SIDs | RFC 9602 | 否 |
| fc00::/7 | 唯一本地地址（ULA）Unique-Local | RFC 4193 | 否 |
| fe80::/10 | 链路本地Link-Local Unicast | RFC 4291 | 否 |
| ff00::/8 | 组播Multicast | RFC 4291 | 否 |
取自 IANA IPv4 与 IPv6 特殊用途地址登记，另加组播和旧的 E 类地址。“可从互联网访问”依据 IANA 的“globally reachable”列。私有地址永远不会在公共互联网上路由。
此内容尚无中文版本。在发布译文之前以英语显示。
Not every IP address is meant to be routed on the internet. IANA keeps two special-purpose address registries, one for IPv4 and one for IPv6, listing the blocks set aside for private networks, loopback, link-local use, documentation, benchmarking, protocol translation and other purposes. Together with the multicast ranges and IPv4’s old class E, they are the addresses a router should never accept as ordinary public destinations, often called bogons.
The ones you are most likely to meet: the three private ranges of RFC 1918 (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) used in almost every home and office network; shared address space 100.64.0.0/10 used by providers for carrier-grade NAT; link-local 169.254.0.0/16 and fe80::/10, which a device gives itself when nothing else configures it; and the documentation blocks (192.0.2.0/24, 198.51.100.0/24, 203.0.113.0/24, 2001:db8::/32) reserved for examples like the ones on this site.
The table is generated from the same registry data this site uses to classify every lookup, and the checker tells you which block an address belongs to, right in your browser.
常见问题
My router's WAN address starts with 100.64. Is that a problem?
It means your provider uses carrier-grade NAT: you share a public IPv4 address with other customers. Browsing works normally, but you cannot open ports to the internet over IPv4. IPv6 or a fixed public address solves it.
Why did my PC get a 169.254.x.x address?
It asked for an address (DHCP) and got no answer, so it assigned itself a link-local address. Check the cable or Wi-Fi connection and the router's DHCP server.
Can I use 192.0.2.0/24 or 2001:db8::/32 in my network?
You should not. They are reserved for documentation, so examples never collide with real networks. Use the private ranges, or unique local addresses (fd00::/8) for IPv6.