Yes, this is something we can accommodate for you at either the NGINX or network level.
Whitelisting IP addresses is a security practice meant to protect your domains or servers from nefarious activity by untrusted users. With a range or single IP authorized for access, you can explicitly limit who is logging into your admin or systems.
For example, if you wanted to restrict outside users from accessing your WordPress admin, whitelisting an IP address would afford you that control. Others outside your approved list will see a 403 Forbidden message when attempting to access it.
You may also want to enable whitelisting for load testing purposes — else our DDoS protections will likely flag your requests and block access temporarily.
Whether you are whitelisting IP addresses for access to production, development, or staging instances, we advise pointing those (sub)domains to the correct CNAME records, ideally at the DNS level. This is to ensure you are passing the GeoCache node locations for your sites to have us properly set up the IP restrictions. Once DNS propagates, any non-whitelisted IP addresses will receive the aforementioned 403 message.
You can whitelist IP addresses directly in your Atomic Control Panel, or you can contact Support — just supply us with the authorized IP address (range) you need whitelisted.
See our related KB articles for details on the self-service option in the Atomic Control Panel: