一般来说直接指定A record就行，这里以NameCheap为例：
@ - used to point a root domain (yourdomain.tld) to the IP address:
//在浏览器输入yourdomain.tld想跳转到的ip
A Record | @ | 11.22.33.44
www - is selected when it is needed to point www.yourdomain.tld to the IP address:
//在浏览器输入www.yourdomain.tld想跳转到的ip
A Record | www | 11.22.33.44
附上NameCheap的详细说明：