CNAME flattening

Benefits

CNAME flattening speeds up DNS resolution and reduces client wait times:

• Fewer DNS queries: Returns the final IP address directly in one query instead of multiple recursive queries.

• Faster response: Fewer queries mean lower overall resolution latency.

• Resolves record conflicts: Converts CNAME records to A/AAAA records, allowing other record types for the same domain.

Use cases

• Use CNAME with other record types: If a domain needs both a CNAME record and other types such as MX or TXT, enable CNAME flattening to convert the CNAME to A/AAAA records and avoid conflicts.

• Optimize DNS queries: CNAME records can trigger multiple recursive queries, increasing latency. CNAME flattening returns the target IP address directly, reducing unnecessary queries.

How it works

When CNAME flattening is enabled and a local DNS queries the A/AAAA record of www.example.com, ESA recursively resolves the CNAME to its final IP address and returns it directly instead of the CNAME record.

Set up CNAME flattening

1. In the ESA console, select Websites. In the Website column, click the target site.

2. In the navigation pane on the left, select DNS > Settings.

3. In the CNAME Flattening area, click Configure and select one of the following options:

   • Flatten CNAME at Root Domain: Flattens only the CNAME records for the root domain (for example, example.com).

   • Flatten All CNAMEs: Flattens the CNAME records for all subdomains.

   

4. Click OK. CNAME records are then flattened based on your configuration.

Verify the results

api.example.com  CNAME  esa.example.icu