ERR_TIMEOUT embedded network_error ai_generated partial

lwIP: 到192.168.1.100:80的TCP连接在3次重传后超时

lwIP: TCP connection to 192.168.1.100:80 timed out after 3 retransmissions

ID: embedded/lwip-tcp-retransmit-timeout

其他格式: JSON · Markdown 中文 · English
80%修复率
90%置信度
1证据数
2024-06-10首次发现

版本兼容性

版本状态引入弃用备注
lwIP v2.1.3 active — — —
lwIP v2.2.0 active — — —
FreeRTOS+TCP v3.0.0 active — — —

根因分析

由于网络拥塞、防火墙阻止或设备电源状态，TCP远程主机不可达或未响应。

English

The TCP remote host is unreachable or not responding due to network congestion, firewall blocking, or device power state.

generic

官方文档

https://savannah.nongnu.org/projects/lwip/

解决方案

  1. Implement a TCP keepalive mechanism using tcp_keepalive() to detect connection failure earlier and reduce retransmission count.
  2. Add a fallback DNS resolution check before connecting: if host resolution fails, abort and retry with exponential backoff.

无效尝试

常见但无效的做法:

  1. Increase the TCP retransmission timeout in lwIP configuration (e.g., TCP_RTO_MIN) 80% 失败

    Longer timeouts only mask the problem; if the remote host is unreachable, the connection will still fail eventually.

  2. Disable TCP checksum offloading on the network interface 95% 失败

    Checksum offloading is unrelated to retransmission timeouts; the issue is network reachability, not data corruption.