DNS Recursion vs DNS Iteration: Key Differences

DNS Recursion:

DNS recursion is a process where a DNS server receives a query from a client and if it does not have the authoritative answer in its cache, it will recursively query other DNS servers until it finds the authoritative answer. This process offloads the burden of finding the answer from the client to the DNS server.

DNS Iteration:

In contrast, DNS iteration is a process where a DNS server does not directly query other DNS servers on behalf of the client. Instead, it provides the client with the list of authoritative DNS servers for the requested domain, and the client is responsible for querying those servers until it finds the authoritative answer. This process puts more workload on the client in terms of querying multiple DNS servers.

In summary, DNS recursion involves the DNS server performing the recursive querying on behalf of the client, while DNS iteration involves the client querying multiple DNS servers until it finds the authoritative answer.