> For the complete documentation index, see [llms.txt](https://befriends.gitbook.io/free-vpn/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://befriends.gitbook.io/free-vpn/vpn.md).

# VPN 知识与使用指南

- [VPN 是什么？VPN 有什么用？普通用户应该怎么选择？](https://befriends.gitbook.io/free-vpn/vpn/vpn-shi-shen-me-vpn-you-shen-me-yong-pu-tong-yong-hu-ying-gai-zen-me-xuan-ze.md)
- [ChatGPT 连不上怎么办？从 DNS、代理到 Clash 的实际排障](https://befriends.gitbook.io/free-vpn/vpn/chatgpt.md)