Hi @hyunchul ,
The document - https://www.gstatic.com/ipranges/goog.json. lists all of the IP addresses used by Google services. These IP addresses can be used for any Google service, including SSL and authentication, but they are not exclusive to any particular service or protocol. SSL is a security protocol that encrypts data between two systems, but it is not tied to any specific IP address. Instead, it can be used on any IP address that supports SSL.
Therefore, any IP address listed in the goog.json document could be used by Google for SSL or authentication. If you are unsure whether an IP address is being used by Google for SSL or authentication, you should cross-reference it with the official list provided in the document. In short, the IP ranges in the goog.json document are for Google services in general, and they can be used for SSL and authentication, but they are not reserved exclusively for those purposes.
Always refer to official Google documentation for accurate and up-to-date information.