A CNAME (Canonical Name) record is a type of DNS (Domain Name System) record used to alias one domain name to another. Essentially, it points a subdomain (like www.yourdomain.com) to the canonical, or true, domain name (such as yourdomain.com or an external service like a hosting provider). This allows you to have multiple domain names resolve to the same IP address without managing separate A records for each.

Think of a CNAME as a domain nickname. For example, if you set a CNAME record for blog.yoursite.com to point to yoursite.com, any visitor accessing the blog subdomain will be directed to the main site. CNAMEs are commonly used for:

• Subdomain routing (e.g., pointing www to the root domain).
• Integrating third-party services (like email, CDNs, or SaaS platforms) without changing your main domain's A record.
• Simplifying DNS management—if the target IP changes, you only update the A record, and all CNAMEs pointing to it automatically reflect the change.

Important limitations: A CNAME record cannot coexist with other records (like MX or TXT) for the same subdomain. Also, it should not point to another CNAME (to avoid performance issues) or be used for the root domain (e.g., yourdomain.com), as this can break other DNS records. For root domains, an A record (pointing to an IP) is required.

To set up a CNAME, access your domain's DNS settings via your hosting provider or registrar. Add a new CNAME record, specify the subdomain (like "www") and the target domain (the canonical name). Changes may take up to 48 hours to propagate globally due to DNS caching.

In summary, a CNAME is a flexible DNS tool for redirecting subdomains, streamlining service integrations, and maintaining consistent web presence. Always verify target domains are valid and avoid circular references to ensure reliable DNS resolution.