https://blog.wongcw.com/2023/04/03/%e5%9c%8b%e5%85%a7%e7%a7%bb%e5%8b%95%e7%b6%b2%e7%b5%a1ipv6%e6%b5%81%e9%87%8f%e7%b5%82%e6%96%bc%e7%aa%81%e7%a0%b450%e5%a4%a7%e9%97%9c%e9%a6%96%e6%ac%a1%e8%b6%85%e8%b6%8aipv4/