# MLDv2：在eth0上未收到组ff02::1:ff00:1234的多播监听者报告

- **ID:** `networking/mldv2-query-no-report`
- **领域:** networking
- **类别:** protocol_error
- **验证级别:** ai_generated
- **修复率:** 82%

## 根因

多播查询器发送了针对特定IPv6组的MLDv2查询，但未收到任何监听者报告，表明该网段上没有活跃的监听者。

## 版本兼容性

| 版本 | 状态 | 引入 | 弃用 |
|------|------|------|------|
| Linux kernel 6.5 | active | — | — |
| OpenWrt 23.05 | active | — | — |
| Cisco IOS XE 17.9 | active | — | — |

## 解决方案

1. ```
   Verify multicast application is running and listening: netstat -an | grep -E 'ff02::1:ff00:1234' ; if missing, restart the application that joins the group
   ```
2. ```
   Check firewall rules on the host that may block MLD reports: sudo ip6tables -L -n | grep mld ; add allow rule if needed: ip6tables -A INPUT -p icmpv6 --icmpv6-type 143 -j ACCEPT
   ```

## 无效尝试

- **** — If no listeners exist, increasing the interval only delays detection; it does not create listeners. (80% 失败率)
- **** — This may cause flooding but does not fix the missing report; the issue is at the host level. (70% 失败率)