托管其他站点时，Web服务器是否需单独购买域名？

Great question—let’s break this down clearly, since this is a common setup when managing your own authoritative DNS and web hosting.

1. 不需要为Web服务器单独购买域名 #

Your web server only needs a publicly accessible IP address (either IPv4 or IPv6) to serve content. You don’t need a dedicated domain for it—you can either:

• Use the server’s raw public IP directly in DNS records, or
• Reuse an existing domain you own (e.g., server.yourdomain.com) with an A/AAAA record pointing to the web server’s IP.

The key here is that the web server’s identity to the internet is its IP; a domain is just a human-friendly alias, not a requirement for it to host other sites.

2. 你的配置思路是可行的，但要注意关键细节 #

Yes, you can host other sites without buying a dedicated domain for your web server, but there’s one critical prerequisite: your authoritative DNS server must have its own registered domain and public IP. Here’s why and how to make it work:

Step 1: Configure the hosted domain’s NS records #

For each site you want to host (e.g., example.com), you need to tell its domain registrar to point the domain’s NS (Name Server) records to your authoritative DNS server’s domain (not just its IP—DNS requires NS records to point to domain names, not raw IPs).

For example:

• If your authoritative DNS server’s domain is ns1.yourdns.com (with an A record pointing to 192.168.1.100), you’d set example.com’s NS records to ns1.yourdns.com (and optionally a secondary NS like ns2.yourdns.com for redundancy).

Step 2: Set up records on your authoritative DNS server #

Once the NS records are propagated, you can configure records for example.com on your DNS server:

• For the root domain (example.com): You can’t use a CNAME record here (DNS standards prohibit CNAME records at the root if you also need other records like MX for email). Instead, create an A/AAAA record pointing directly to your web server’s public IP.
• For subdomains (www.example.com, blog.example.com): You can safely use a CNAME record pointing to your existing web server alias (e.g., server.yourdomain.com or even the raw IP, though CNAME to a domain is cleaner).

Example configuration snippet #

Suppose your web server IP is 192.168.1.200, and you have an existing record server.yourdomain.com → 192.168.1.200:

example.com.   IN  A   192.168.1.200
www.example.com.   IN  CNAME   server.yourdomain.com.

Quick recap #

• No need for a dedicated domain for your web server—its public IP is enough.
• Your authoritative DNS server does need its own registered domain (so other domains can point their NS records to it).
• Root domains of hosted sites need A/AAAA records, subdomains can use CNAMEs for simplicity.

内容的提问来源于stack exchange，提问作者roland