DNS
Domain Name System
ELI5 — The Vibe Check
DNS is the internet's phonebook. You type 'google.com' and DNS looks up the actual number (IP address) behind it, like looking up 'John' in your contacts to get his phone number. Without DNS you'd have to memorize numbers for every website.
Real Talk
DNS is a hierarchical, distributed naming system that translates human-readable domain names into IP addresses. It uses a tree structure with root servers, TLD servers (.com, .org), and authoritative nameservers for each domain.
Show Me The Code
# Query DNS records
nslookup google.com
# Using dig
dig google.com A
dig google.com MX
dig @8.8.8.8 example.com
When You'll Hear This
"DNS propagation can take up to 48 hours." / "The DNS lookup is failing — check the nameservers."
Related Terms
A Record
An A Record is the most basic DNS record — it just says 'this domain name = this IP address.' It's the phonebook entry itself.
CNAME (Canonical Name Record)
A CNAME is a DNS record that's like an alias or nickname. Instead of pointing to an IP address directly, it points to another domain name. So 'www.
Domain Name
A domain name is the human-friendly name for a website, like 'google.com' instead of '142.250.80.46'.
MX Record (Mail Exchange Record)
An MX record tells the internet where to deliver emails for your domain. When someone sends an email to you@yoursite.
Nameserver
A nameserver is the specific server that actually knows all the DNS records for your domain — it's the authoritative source of truth.
TTL (Time To Live)
TTL is how long DNS resolvers are allowed to remember (cache) your DNS records before checking again. A TTL of 3600 means 'remember this for 1 hour.