Frontend Awareness

DNS (Domain Name System) translates human-readable domain names into IP addresses.

How it works:

1. User types example.com in the browser

2. Browser checks local cache for the IP

3. If not cached, queries the recursive resolver (ISP's DNS server)

4. Resolver checks its cache, then queries root nameserver

5. Root directs to .com TLD nameserver

6. TLD directs to authoritative nameserver for example.com

7. Authoritative server returns the IP address

8. Browser connects to the IP

DNS Records:

A — Maps domain to IPv4

AAAA — Maps domain to IPv6

CNAME — Alias for another domain

MX — Mail server

TXT — Verification, SPF, DKIM

Authentication — Verifying WHO you are

"Are you who you claim to be?"

Login with username/password

Biometric verification

Multi-factor authentication (MFA)

Authorization — Determining WHAT you can access

"Are you allowed to do this?"

Role-based access (admin, user, guest)

Permissions and policies

API scopes and tokens

| Aspect | Authentication | Authorization |

|--------|---------------|---------------|

| Purpose | Verify identity | Check permissions |

| Order | First | After authentication |

| Example | Login form | Admin-only page |

| Mechanism | Passwords, tokens, biometrics | Roles, policies, ACLs |

Authentication answers "Who are you?" while authorization answers "What can you do?"