Table of Contents
Recursive Resolver vs Authoritative DNS Server
DNS involves two fundamentally different types of servers:
- Recursive Resolvers
- Authoritative DNS Servers
Although both answer DNS queries, they perform very different roles.
Recursive Resolver
A recursive resolver is the DNS server that users query directly.
Examples include:
- Google Public DNS (`8.8.8.8`)
- Cloudflare DNS (`1.1.1.1`)
- Quad9 (`9.9.9.9`)
- Your ISP's DNS servers
Its responsibilities are:
- Receive DNS queries from users.
- Search its cache.
- Perform recursive lookups if necessary.
- Cache the results according to TTL.
- Return the final answer to the client.
User │ ▼ Recursive Resolver
Authoritative DNS Server
An authoritative server stores the official DNS records for a domain.
Example:
example.com
│
▼
ns1.example.com
It does not perform recursive lookups.
Instead, it simply answers questions about domains for which it is authoritative.
Typical records include:
- A
- AAAA
- MX
- TXT
- NS
- SOA
- CAA
Query Flow
Suppose a user requests:
www.example.com
The lookup proceeds as follows:
Browser │ ▼ Recursive Resolver │ ▼ Root Server │ ▼ TLD Server │ ▼ Authoritative Server │ ▼ Answer
The browser communicates only with the recursive resolver.
Comparison
| Recursive Resolver | Authoritative Server |
|---|---|
| Receives queries from users | Stores official DNS records |
| Performs recursive lookups | Never performs recursion |
| Uses cache | Does not cache other domains |
| Returns cached answers | Returns authoritative answers |
| Usually operated by ISPs or public DNS providers | Usually operated by DNS hosting providers |
Why Responses May Differ
Recursive resolvers may return different answers because:
- Their cache has not expired.
- They are located in different countries.
- CDN or GeoDNS returns different IP addresses.
- DNS propagation is still in progress.
Authoritative servers, however, always return the current published records.
Can I Query the Authoritative Server Directly?
Yes.
For example:
dig @ns1.example.com example.com A
This bypasses recursive resolvers and asks the authoritative server directly.
This is useful for verifying that recent DNS changes have been published.
How Telenegar DNS Check Works
Telenegar DNS Check queries multiple recursive DNS providers around the world.
This allows you to:
- Compare DNS responses.
- Detect propagation delays.
- Observe GeoDNS behavior.
- Compare public DNS providers.
Telenegar also supports querying authoritative DNS servers directly, allowing you to compare published records with what recursive resolvers currently return.
Common Misconceptions
- Recursive DNS servers own the DNS records.
- False. They only cache and forward queries.
- Authoritative servers cache Internet DNS records.
- False. They only answer for their own zones.
- Google DNS is authoritative for every domain.
- False. Google Public DNS is only a recursive resolver.
Related Topics
dns resolver authoritative recursion nameserver