Understanding DNS
> Article · KB-1042 — Last updated June 4, 2026 · 4 min read · Category: Networking
The Domain Name System (DNS) is the part of the internet that turns human-friendly names like example.com into the numeric IP addresses computers use to find each other. Without it, you'd have to memorize a string of numbers for every site you visit.
How a lookup works
When you type an address into your browser, several steps happen in the background — usually in a few milliseconds:
- Your device checks its local cache to see if it already knows the answer.
- If not, the request goes to a resolver (often run by your ISP or a provider like
1.1.1.1). - The resolver asks the root and top-level domain servers where to find the domain.
- The domain's authoritative server returns the matching IP address.
- The answer is cached and handed back to your browser, which connects to the server.
sequenceDiagram
participant B as Browser
participant R as Resolver
participant Root as Root Server
participant TLD as TLD Server (.com)
participant Auth as Authoritative Server
B->>R: Where is example.com?
Note over R: Check cache first
R->>Root: Where is .com?
Root-->>R: Ask the .com TLD server
R->>TLD: Where is example.com?
TLD-->>R: Ask example.com's authoritative server
R->>Auth: What is the IP for example.com?
Auth-->>R: 93.184.216.34
R-->>B: 93.184.216.34 (cached for TTL)
B->>Auth: Connect to 93.184.216.34
Common record types
A DNS zone is made up of records. These are the ones you'll run into most often:
| Type | Purpose | Example value |
|---|---|---|
A |
Points a name to an IPv4 address | 93.184.216.34 |
AAAA |
Points a name to an IPv6 address | 2606:2800:220:1:: |
CNAME |
Aliases one name to another | shop.example.com |
MX |
Directs email to mail servers | mail.example.com |
TXT |
Holds text, often for verification | v=spf1 include:... |
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