github_pages

Reference

https://help.github.com/articles/troubleshooting-custom-domains/

A records

185.199.108.153

185.199.109.153

185.199.110.153

185.199.111.153

You may see a different IP address, since we serve Pages with a global Content Delivery Network. Use dig username.github.io to see the full resolution path. Note that DNS caching may cause a delay.

Over HTTPS

If you're using an A record that points to 192.30.252.153 or 192.30.252.154, you'll need to update your DNS settings for your site to be available over HTTPS or served with a Content Delivery Network. For more information, see "HTTPS errors."

Discontinue

If you're using an A record that points to 207.97.227.245 or 204.232.175.78, you'll need to update your DNS settings, as we no longer serve Pages directly from those servers.

CNAME

If you configured ALIAS, ANAME, or CNAME records through your DNS provider, then your DNS record should point to your GitHub Pages default domain, such as YOUR-GITHUB-USERNAME.github.io. Your default GitHub Pages domain is determined by the type of pages site you have. For examples, see this domain chart.

If you need help creating these records, contact your DNS provider as they should have the most detailed instructions. For some guidelines on configuring a DNS record with DNS providers, see "Using a custom domain with GitHub Pages."