What does a CNAME record do in DNS settings?

A CNAME record, or Canonical Name record, serves a specific function in the Domain Name System (DNS) by mapping an alias to another domain name. This is particularly useful when you want to point multiple domain names to a single canonical domain without needing to manage multiple A records, which directly map domain names to IP addresses.

For example, if you have several subdomains like www.example.com, blog.example.com, and shop.example.com, you can set them up as CNAME records that point to the primary domain name (e.g., example.com). This way, any changes to the primary domain's IP address will automatically be reflected on all subdomains without needing to update each one individually.

The other options describe different DNS functions. Mapping an IP address to a domain typically involves an A record, routing traffic to an application server is more related to load balancers or reverse proxies rather than DNS records, and defining security policies for websites falls under web application firewalls or security services, not DNS settings. Therefore, the function of the CNAME record in linking an alias to another domain is key to simplifying domain management and ensuring consistent routing across related web properties.