A domain can often be reached with or without the www prefix. The important issue is consistent configuration, not a universal requirement to use one format.

Choose One Preferred Hostname

Select the primary hostname and permanently redirect the alternate version to it. Internal links, canonical URLs, sitemaps, and marketing materials should consistently use the preferred hostname.

Verify

• Both hostnames resolve.
• The certificate covers the needed hostnames.
• The alternate redirects correctly.
• Canonical URLs use the preferred hostname.
• Cookies and application settings behave correctly.

Changing the hostname of an established site requires careful redirects and monitoring.