What is DNS and how does it work?

Question

Accepted Answer

**DNS** — Domain Name System. Translates domain names to IP addresses.

**How it works:**
```
1. User types "example.com"
2. Browser checks local cache
3. If not found → recursive resolver
4. Resolver queries root nameservers
5. Root → TLD nameservers (.com)
6. TLD → authoritative nameservers
7. Authoritative returns IP
8. Browser connects to IP
```

**DNS Record Types:**
```
A     — IPv4 address
AAAA  — IPv6 address
CNAME — alias to another domain
MX    — mail server
TXT   — text information
NS    — nameserver
SOA   — zone authority
```

**DNS Hierarchy:**
```
Root (.) → TLD (.com) → Domain (example.com)
```

**Caching:** Results cached at multiple levels.

Systems Analyst: What is DNS and how does it work?