What is DNS?
DNS (Domain Name System) is like the phone book of the internet. It translates easy-to-remember website names (like www.example.com) into the numeric IP addresses that computers use to find each other.
Let's break it down
- Domain Name System: a system that keeps a list of names and numbers.
- Domain name: the readable address you type, e.g., “google.com”.
- IP address: a series of numbers (like 172.217.3.110) that identifies a computer on the network.
- Translate: change one form (name) into another (number) so devices can understand each other.
Why does it matter?
Without DNS, you would have to remember the long strings of numbers for every website you want to visit. DNS makes browsing fast, user-friendly, and lets the internet work smoothly for everyone.
Where is it used?
- Loading any website in a web browser.
- Sending an email, where the mail server’s domain name is looked up first.
- Using a smartphone app that connects to an online service by its domain name.
- Accessing cloud services (e.g., storage, streaming) that rely on DNS to locate servers.
Good things about it
- Simplicity: users only need to remember words, not numbers.
- Speed: caching DNS records lets devices find sites quickly.
- Scalability: works for billions of devices worldwide.
- Flexibility: domain names can be moved to different servers without changing the user-visible address.
Not-so-good things
- Dependency: if DNS servers go down, you can’t reach sites even though the sites are up.
- Security risks: attackers can hijack DNS records (DNS spoofing) to redirect users to malicious sites.
- Latency: a slow DNS lookup adds a small delay before a page starts loading.
- Complexity of management: large organizations need careful DNS configuration to avoid errors.