A DNS recursive resolver acts as an intermediary between a user’s device and the authoritative DNS servers that hold the final answers to domain name lookups. When you type a website address into your browser, your device sends a DNS query to a recursive resolver. Here’s how it works:
Query Handling:
- The resolver receives your request and, if it doesn’t already have the answer cached, it begins a process of querying other DNS servers.
- It starts by contacting root servers, then progresses to top-level domain (TLD) servers, and finally to the authoritative name servers for the specific domain you’re trying to reach.
The Recursive Process:
- This “recursive” process means that the resolver takes on the responsibility of tracking down the IP address, rather than making your device do it.
- It continues to query different DNS servers until it finds the correct IP address.
Caching:
- Once the resolver obtains the IP address, it caches it for a period of time. This speeds up subsequent requests for the same domain.
- This caching is a very important part of speeding up internet browsing.
In Summary: Therefore a recursive resolver is a server that will preform all of the lookups needed to resolve a domain name, and then return the answer to the client.
