How do I create a subdomain using DNS?
Creating a subdomain through DNS requires adding specific DNS records to your domain's DNS zone. You'll need to configure either an A record (pointing to an IP address) or a CNAME record (pointing to another domain) for your subdomain. This process involves accessing your DNS management interface, creating the appropriate record type, and waiting for DNS propagation to complete across global servers.
Understanding Subdomain Creation Through DNS
A subdomain functions as a separate section of your main domain, appearing before your primary domain name (like blog.yoursite.com). The DNS (Domain Name System) serves as the internet's address book, translating human-readable domain names into IP addresses that computers understand.
When you create a subdomain, you're essentially telling the DNS system where to direct visitors who type that specific address. Without proper DNS configuration, your subdomain won't resolve to any server, making it inaccessible to users.
DNS management becomes necessary because subdomains require their own routing instructions. Your main domain might point to one server, whilst your subdomain could direct traffic to a completely different location or service. This flexibility allows you to host different applications, services, or content sections on separate infrastructure whilst maintaining a cohesive domain structure.
What DNS Records Do You Need for a Subdomain?
Creating a subdomain requires one of two primary DNS record types: A records or CNAME records. A records directly map your subdomain to an IPv4 address, whilst CNAME records create an alias pointing to another domain name.
A records work best when you know the exact IP address of your target server. For example, if your subdomain should point to 192.168.1.100, you'd create an A record with that specific address. This method provides direct routing without additional DNS lookups.
CNAME records prove more flexible for dynamic hosting environments. Instead of pointing to an IP address, they reference another domain name. When someone visits your subdomain, the DNS system performs an additional lookup to resolve the target domain's current IP address.
| Record Type | Points To | Best Use Case |
|---|---|---|
| A Record | IPv4 Address | Static server configurations |
| CNAME Record | Domain Name | Dynamic hosting or CDN services |
| AAAA Record | IPv6 Address | IPv6-enabled servers |
How Do You Configure DNS Records for a New Subdomain?
Configuring DNS records involves accessing your domain's DNS management interface and creating the appropriate record entries. Most hosting providers offer web-based control panels that simplify this process through intuitive forms and dropdown menus.
Start by logging into your DNS management dashboard. Look for sections labelled "DNS Management," "DNS Zone Editor," or "Domain Settings." Navigate to the area where you can add new DNS records.
Create your subdomain record by selecting the record type (A or CNAME), entering your subdomain name in the "Name" or "Host" field, and specifying the target (IP address for A records, domain name for CNAME records). Set the TTL (Time To Live) value, which determines how long DNS servers cache your record.
Advanced users can configure DNS records through command line interfaces or API calls. Many cloud providers offer CLI tools that allow batch record creation and automated DNS management through scripts.
Why Isn't My Subdomain Working After DNS Setup?
DNS propagation delays represent the most common reason subdomains don't work immediately after configuration. DNS changes can take 24-48 hours to propagate across all global DNS servers, though most changes become visible within a few hours.
Record conflicts occur when multiple DNS entries exist for the same subdomain. Check your DNS zone for duplicate records or conflicting entries that might prevent proper resolution. Remove any outdated or incorrect records that could interfere with your new configuration.
Configuration errors often involve incorrect syntax or missing components. Verify that your subdomain name doesn't include the main domain (enter "blog" not "blog.yoursite.com" in the name field). Ensure IP addresses follow proper formatting and CNAME targets end with a period if required by your DNS provider.
Firewall restrictions or server misconfigurations can also prevent subdomain access even when DNS resolves correctly. Test your subdomain using DNS lookup tools to confirm the records resolve properly, then investigate server-side issues if DNS appears correct.
What's the Difference Between Subdomain Hosting and DNS Configuration?
DNS configuration and subdomain hosting represent two distinct but interconnected processes. DNS setup tells the internet where to find your subdomain, whilst hosting provides the actual server resources and content that visitors access.
Think of DNS as providing directions to a location, whilst hosting supplies the actual building and contents at that address. You can configure DNS records perfectly, but without proper hosting infrastructure, visitors will encounter error messages when they reach the specified server.
Subdomain hosting requires server resources, web server configuration, and content delivery capabilities. Your hosting environment must recognise and respond to requests for your specific subdomain. This often involves virtual host configuration, SSL certificate setup, and application deployment.
Many cloud providers integrate DNS management with hosting services, allowing you to configure both simultaneously. This integration streamlines the process and reduces potential configuration mismatches between DNS records and hosting settings.
Making Subdomain Creation Work for Your Infrastructure
Successful subdomain implementation combines proper DNS configuration with robust hosting infrastructure. Understanding both components helps you create scalable, reliable subdomain architectures that support your business requirements.
Best practices include using consistent naming conventions, implementing proper monitoring for DNS resolution, and maintaining documentation of your subdomain structure. Regular audits help identify unused subdomains and optimise your DNS configuration.
At Falconcloud, we provide comprehensive DNS management tools alongside our cloud infrastructure services. Our global data centres ensure reliable subdomain hosting, whilst our integrated DNS management simplifies the entire configuration process. Whether you need simple subdomain setup or complex multi-region configurations, our platform supports scalable DNS and hosting solutions that grow with your infrastructure needs.
