> For the complete documentation index, see [llms.txt](https://hacking-notes.jord4n.pro/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hacking-notes.jord4n.pro/zh/ports-and-services/ftp-21.md).
# FTP - 21
当暴露了匿名访问、可写目录、备份文件或 Web 根目录上传时，FTP 往往会变得很有用。首先检查版本信息、匿名登录、写入权限，以及上传的文件是否能通过 Web 服务访问。
## 备注
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