How to Set Up a Subdomain with DNS

Subdomains are prefixes to your main domain (like blog.example.com). They can point to the same server, different servers, or third-party services.

Creating a Subdomain

There are two steps:

1. Add DNS record for the subdomain
2. Configure hosting to serve content (if hosting locally)

Method 1: Subdomain on Same Server

If hosting the subdomain on Ahosting:

1. Go to cPanel > Domains
2. Click Create A New Domain
3. Enter full subdomain: blog.example.com
4. Click Submit

cPanel automatically creates the DNS record and folder.

Method 2: Subdomain to Different IP

If pointing to a different server:

1. Go to Zone Editor
2. Click + A Record
3. Name: blog (the subdomain prefix)
4. Address: The destination IP address
5. Click Add Record

Method 3: Subdomain to External Service

If pointing to a third-party service (Shopify, Tumblr, etc.):

1. Go to Zone Editor
2. Click + CNAME Record
3. Name: shop (the subdomain prefix)
4. Record: shops.myshopify.com (service hostname)
5. Click Add Record

Common Subdomain Configurations

Subdomain	Record Type	Points To
www	A or CNAME	Same server or example.com
blog	A	Same server IP
shop	CNAME	shops.myshopify.com
mail	A	Mail server IP
staging	A	Development server IP
app	A	Application server IP

Wildcard Subdomain

A wildcard record handles all undefined subdomains:

*.example.com    A    192.168.1.1

Any subdomain not specifically defined will use this record.

SSL for Subdomains

Each subdomain needs its own SSL certificate or a wildcard certificate.

• AutoSSL: Automatically covers subdomains added in cPanel
• Wildcard SSL: Covers *.example.com with one certificate
• External services: Usually provide their own SSL

Subdomain Email

You can create email addresses for subdomains:

• [email protected]
• [email protected]

MX records can be added for subdomains if needed.

Testing Subdomain Setup

1. Wait for DNS propagation (few minutes to hours)
2. Use nslookup or dig to verify record:

   nslookup blog.example.com

3. Try accessing in browser

Troubleshooting

Subdomain not resolving

• Check DNS record exists in Zone Editor
• Wait for propagation
• Verify no typos in subdomain name

Subdomain shows wrong content

• Verify document root is correct in cPanel
• Check A record points to correct IP
• Clear browser cache

SSL not working on subdomain

• Run AutoSSL from cPanel
• Wait for certificate issuance
• Check subdomain is added in cPanel Domains