A and AAAA
Associate a name with an IPv4 or IPv6 address.
web destinations
Internet infrastructure
What is DNS?
The Domain Name System is a distributed naming system. It lets software ask for records attached to names, including addresses for websites, mail routes and proof used by other services.
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The core concept
DNS maps names to typed records
A lookup asks a specific question. The returned record type determines how the answer is interpreted.
example.comName
›
AQuestion
›
192.0.2.1Answer
The example address is reserved for documentation. Real domains can return multiple records and can change those records over time.
The essentials
CNAME
Makes one hostname an alias of another canonical hostname.
www → host.example
MX
Identifies the mail exchangers that accept email for a domain.
email routing
TXT
Carries text used for verification and policies such as SPF or DKIM.
proof · email policy
The two sides of a DNS lookup
Recursive resolvers search on the user's behalf; authoritative servers publish the domain owner's data.
The application asks
A browser, mail server or other application asks for a record type at a name.
The resolver checks cache
A valid cached answer can be returned immediately.
The resolver follows referrals
Without cache, it follows the DNS hierarchy toward the authoritative zone.
The answer is cached
The record is returned and may be reused until its TTL expires.
Common DNS records at a glance
Use the record your service provider specifies; similar-looking records are not interchangeable.
| Type | Purpose | Typical value |
|---|---|---|
| A | IPv4 destination | 192.0.2.1 |
| AAAA | IPv6 destination | 2001:db8::1 |
| CNAME | Hostname alias | target.example.net |
| MX | Mail exchanger with priority | 10 mail.example.net |
| TXT | Text policy or verification | provider-specific text |
| NS | Authoritative nameserver | ns1.example.net |
Avoid the most common DNS mistakes
- Edit records at the provider named by the current authoritative nameservers.
- Copy the hostname and value exactly as the receiving service specifies.
- Do not replace nameservers without recreating every required record.
- Use low TTLs temporarily for planned changes, then restore a sensible value.
- Keep mail records intact when moving only the website.
- Check for conflicting records at the same hostname before adding a CNAME.
Common questions
Is DNS the same as a domain name?
No. The domain is a name in the namespace. DNS is the system that stores and retrieves typed records associated with names.
What does DNS propagation mean?
It usually describes old cached answers expiring across many resolvers. There is no single propagation switch; each cached answer follows its own TTL.
Can a domain work for email but not a website?
Yes. Mail and web use different records. Correct MX records can route email even when the web hostname has no working address.
Does DNS provide HTTPS security?
DNS locates services; HTTPS authenticates and encrypts the browser connection. DNSSEC can protect DNS data integrity, but it does not replace HTTPS.
Keep learning
The next concepts to understand
Next step
Check DNS alongside registration data
Search a domain and see whether registry and DNS signals agree before you act.