Recursive DNS and authoritative DNS are both essential components of the Domain Name System (DNS), but they play different roles.
Here’s a table that summarizes the key differences between recursive DNS and authoritative DNS:
| Feature | Recursive DNS | Authoritative DNS |
|---|---|---|
| Role | Intermediary between client and authoritative DNS servers | Source of DNS record information |
| Function | Resolves DNS queries by contacting authoritative DNS servers | Provides definitive answers to DNS queries |
| Information | Stores cached DNS records | Holds the master copy of DNS records for a specific zone |
| Purpose | Speeds up DNS resolution by caching frequently accessed records | Ensures the accuracy and up-to-dateness of DNS records |
Recursive DNS
A recursive DNS server is like a librarian. When you ask a librarian for a book, they check the library’s catalog to see if the book is available. If it is, they will give you the book. If it is not, they will help you find another library that has the book.
In the same way, a recursive DNS server receives a DNS query from a client and checks its cache to see if it has the answer. If it does, it will return the answer to the client. If it does not, it will contact the appropriate authoritative DNS server to get the answer.
Authoritative DNS
An authoritative DNS server is like the publisher of a phone book. It holds the master copy of DNS records for a specific zone. When a recursive DNS server contacts an authoritative DNS server, it is asking the publisher of the phone book for the listing of a particular person or business.
The authoritative DNS server will return the requested DNS record to the recursive DNS server. The recursive DNS server will then cache the record and return it to the client.
Benefits of using a recursive DNS server
There are several benefits to using a recursive DNS server, including:
- Speed: Recursive DNS servers can speed up DNS resolution by caching frequently accessed records.
- Scalability: Recursive DNS servers can handle a large volume of DNS queries without being overwhelmed.
- Reliability: Recursive DNS servers are typically very reliable and rarely go down.
Benefits of using an authoritative DNS server
There are also several benefits to using an authoritative DNS server, including:
- Accuracy: Authoritative DNS servers hold the master copy of DNS records, so they are always accurate and up-to-date.
- Control: Authoritative DNS servers give domain owners control over their DNS records.
- Reliability: Authoritative DNS servers are typically very reliable and rarely go down.
