https://blog.gongquiz.com/2022/01/01/%eb%8b%a4%ec%9d%8c-%ec%84%a4%eb%aa%85%ec%97%90-%ed%95%b4%eb%8b%b9%ed%95%98%eb%8a%94-dns-%ec%84%9c%eb%b2%84%ec%9d%98-%ec%a2%85%eb%a5%98%eb%a1%9c-%ea%b0%80%ec%9e%a5-%ec%95%8c%eb%a7%9e%ec%9d%80-%ea%b2%83/