# NDP：在eth0上检测到fe80::1的重复地址，重复地址检测失败

- **ID:** `networking/ndp-duplicate-address`
- **领域:** networking
- **类别:** layer2
- **验证级别:** ai_generated
- **修复率:** 81%

## 根因

IPv6链路本地地址的重复地址检测（DAD）失败，因为同一链路上的另一台主机已在使用该地址，通常是由于手动配置重叠或恶意设备。

## 版本兼容性

| 版本 | 状态 | 引入 | 弃用 |
|------|------|------|------|
| Linux kernel 6.1.0-17-amd64 | active | — | — |
| Windows Server 2022 IPv6 stack | active | — | — |
| Cisco IOS 15.9(3)M | active | — | — |
| FreeBSD 14.0 | active | — | — |

## 解决方案

1. ```
   Manually assign a unique link-local address on the local host: `ip addr add fe80::2/64 dev eth0` and remove the conflicting one
   ```
2. ```
   Identify the conflicting host by scanning the neighbor cache: `ip -6 neigh show dev eth0`, then disconnect or reconfigure it
   ```

## 无效尝试

- **** — This allows duplicate addresses to persist, causing packet loss and connectivity issues for both hosts. (90% 失败率)
- **** — The duplicate address is still used by the other host; the local host may get a new address but the conflict is not resolved. (70% 失败率)
- **** — The duplicate address on the remote host remains; the local host will generate the same address again based on its MAC, leading to the same DAD failure. (80% 失败率)