> For the complete documentation index, see [llms.txt](https://blog.xn--ss-8ja.vn/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://blog.xn--ss-8ja.vn/mot-so-dieu-ban-can-biet.md).

# Một số điều bạn cần biết 

- [VPN là gì ?](https://blog.xn--ss-8ja.vn/mot-so-dieu-ban-can-biet/vpn-la-gi.md)
- [Ưu và nhược điểm khi sử dụng VPN](https://blog.xn--ss-8ja.vn/mot-so-dieu-ban-can-biet/uu-va-nhuoc-diem-khi-su-dung-vpn.md)
- [Ping là gì ?](https://blog.xn--ss-8ja.vn/mot-so-dieu-ban-can-biet/ping-la-gi.md)
- [Hack 4G là gì ?](https://blog.xn--ss-8ja.vn/mot-so-dieu-ban-can-biet/hack-4g-la-gi.md)
- [Chính sách hoàn tiền](https://blog.xn--ss-8ja.vn/mot-so-dieu-ban-can-biet/chinh-sach-hoan-tien.md)