Github Pages绑定域名09 Mar 2020
A common problem encountered with CNAME records when integrating with 3rd party site hosting services is that www.domain.com CNAME records are easily created, but creating the CNAME record for just domain.com (to capture traffic when people don’t type in “www.”) cannot be done since that goes against RFC1034. We have a work around for customers with this issue - our domain parking system redirects any “naked” domains (i.e. the SLD - domain.com) to the www.domain.com equivalent. Therefore, all that must be done is to create an A record to our parking IP (which can be done by applying the parking/forwarding DNS template) for the SLD hostname.
wwwsubdomains are the most stable type of custom domain because
wwwsubdomains are not affected by changes to the IP addresses of GitHub’s servers. Your site will also load faster because Denial of Service (DoS) attack protection can be implemented more efficiently.