In case if you need to fetch your content from a particular IP other than from your defined domain, you can specify that IP under Origin IP Resolution. It resolves your domain from the defined IP, so that CDN contact your server by IP instead of the domain. To do this go to your Pull Zone > Origin IP Resolution. Then provide the IP from which you want to fetch the contents.
You can also provide Custom Host Header to identify your site, in case your Webserver has more than one website. For example, if your web server has IP address 188.8.131.52, and there are websites: [firstwebsite.com](), [secondwebsite.com](), [thirdwebsite.com]() and if we are requesting 184.108.40.206, and we put custom host header as "secondwebsite.com", then that particular website will be cached.