@
abelyao 这方面 CloudFlare 做出了很清楚的说明(就是这帮人折腾出了“ CNAME Flattening ”):
https://blog.cloudflare.com/introducing-cname-flattening-rfc-compliant-cnames-at-a-domains-root/“ Technically, the root could be a CNAME but the RFCs state that once a record has a CNAME it can't have any other entries associated with it: that's a problem for a root record like
example.com because it will often have an MX record (so email gets delivered), an NS record (to find out which nameserver handles the zone) and an SOA record.”
裸域可以用 CNAME ,主要代价是失去 MX 记录(电子邮件,反正你不用哈), NS 记录(下面再接着说), SOA 记录。
裸域的 NS 记录:
https://blog.dnsimple.com/2015/04/common-dns-records/“ The benefit of having multiple NS records on the apex zone is additional redundancy of DNS service.”
因为你域名的注册商那里,就可以设置域名解析服务器,所以此处 NS 记录是“冗余”( redundancy )。
我也是以前遇到过类似问题,自己不是专业系统管理员啦,欢迎拍砖 :-)