What will the DNS server do if it cannot resolve a lookup request using its zones?

When a DNS server receives a lookup request that it cannot resolve using its own zones, it typically attempts to perform a recursive query using the root hints. Root hints are predefined IP addresses of DNS root servers that provide a way for the DNS server to start the resolution process.

In this context, if the DNS server doesn't have the answer in its local database (its zones), it will use the information it has about the root servers to begin the resolution process from the top of the DNS hierarchy. This progression involves querying the root name servers to find out which name servers are authoritative for the domain being requested, thus allowing the server to eventually resolve the DNS lookup.

This behavior relies on the server's ability to reach and communicate with the root servers, which are fundamental components of the global Domain Name System. It ensures that even in the absence of locally stored data for a domain, there is still a method for obtaining the required information by traversing the DNS structure.