如何排查 nginx 访问日志里的 400 响应码？

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这是一个创建于 1142 天前的主题，其中的信息可能已经有所发展或是发生改变。

就是每分钟有一条来自自己其它服务器公网 IP 的访问记录，看不出哪里的问题，有人遇到这种问题吗？

47.100.xxx.xx - - [22/Feb/2023:09:08:32 +0800] "" 400 0 "-" "-"
47.100.xxx.xx - - [22/Feb/2023:09:09:32 +0800] "" 400 0 "-" "-"
47.100.xxx.xx - - [22/Feb/2023:09:10:32 +0800] "" 400 0 "-" "-"
47.100.xxx.xx - - [22/Feb/2023:09:11:32 +0800] "" 400 0 "-" "-"
47.100.xxx.xx - - [22/Feb/2023:09:12:32 +0800] "" 400 0 "-" "-"
47.100.xxx.xx - - [22/Feb/2023:09:13:32 +0800] "" 400 0 "-" "-"
47.100.xxx.xx - - [22/Feb/2023:09:14:32 +0800] "" 400 0 "-" "-"
47.100.xxx.xx - - [22/Feb/2023:09:15:32 +0800] "" 400 0 "-" "-"
47.100.xxx.xx - - [22/Feb/2023:09:16:32 +0800] "" 400 0 "-" "-"
47.100.xxx.xx - - [22/Feb/2023:09:17:32 +0800] "" 400 0 "-" "-"
47.100.xxx.xx - - [22/Feb/2023:09:18:32 +0800] "" 400 0 "-" "-"

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Feb 47.100.xxx 23:09:17 23:09:16