Domain Name System (DNS) Explained: Examples and How it Works

📚 Quick Study Guide

• 🌍 The Domain Name System (DNS) translates domain names (like google.com) into IP addresses (like 172.217.160.142) that computers understand.
• 🧭 DNS resolvers act as intermediaries between your computer and DNS servers.
• 🏛️ Root DNS servers are at the top of the DNS hierarchy.
• 🔑 Authoritative DNS servers hold the final, correct IP address information for a domain.
• ⏱️ DNS records have a Time To Live (TTL) value that determines how long the information is cached.
• ⚙️ Common DNS record types include: A (maps hostname to IPv4 address), AAAA (maps hostname to IPv6 address), CNAME (maps an alias hostname to a canonical hostname), MX (specifies mail servers), and TXT (holds arbitrary text).
• 💡 DNS lookup process: Your computer queries a DNS resolver, which recursively queries root, TLD, and authoritative servers until it finds the IP address.

🧪 Practice Quiz

1. Which of the following best describes the primary function of DNS?
   1. A. To manage network hardware.
   2. B. To translate domain names to IP addresses.
   3. C. To encrypt internet traffic.
   4. D. To optimize website loading speed.
2. What type of DNS server holds the final, correct IP address information for a domain?
   1. A. Root DNS server
   2. B. Recursive DNS server
   3. C. Authoritative DNS server
   4. D. Top-Level Domain (TLD) server
3. What does the DNS record type 'A' primarily store?
   1. A. IPv6 Address
   2. B. IPv4 Address
   3. C. Mail Exchange Server
   4. D. Canonical Name
4. What is the role of a DNS resolver?
   1. A. To directly manage domain registrations.
   2. B. To act as an intermediary and query DNS servers on behalf of a client.
   3. C. To host website content.
   4. D. To prevent DDoS attacks.
5. What does TTL (Time To Live) in a DNS record determine?
   1. A. The server's physical location.
   2. B. The duration for which a DNS record is cached.
   3. C. The maximum bandwidth allocation.
   4. D. The encryption strength of the connection.
6. Which DNS record is used to specify mail servers for a domain?
   1. A. A
   2. B. CNAME
   3. C. MX
   4. D. TXT
7. Which of the following is a function of the Root DNS server?
   1. A. Resolving all domain names directly.
   2. B. Directing queries to the appropriate TLD servers.
   3. C. Storing all DNS records globally.
   4. D. Caching all DNS queries.