Web & Network • 7 min read • Last updated: Thu Feb 01 2024 00:00:00 GMT+0000 (Coordinated Universal Time)

IP Addresses and DNS

The internet is just a wire (or radio wave) connecting computers. To send a message to a specific computer, you need its address.

The IP Address

Every device connected to the internet has an IP Address (Internet Protocol).

  • IPv4: 192.168.1.1 (The old standard. We ran out of these).
  • IPv6: 2001:0db8:85a3:0000:0000:8a2e:0370:7334 (The new standard. Virtually infinite).

Think of an IP address like a phone number. It locates the specific device.

The DNS (Domain Name System)

Humans are bad at remembering numbers. You don't want to type 142.250.190.46 to get to Google. You want to type google.com.

DNS is the Phone Book of the internet. It maps human names to IP addresses.

How it works (Simplified)

You DNS Server Website 1. "Where is google.com?" 2. "It's at 142.250..." 3. Connects directly via IP
  1. Request: You type example.com.
  2. Lookup: Your computer asks a DNS Server (usually provided by your ISP): "Who is example.com?"
  3. Response: The Server replies: "That is 93.184.216.34".
  4. Connect: Your computer caches (remembers) this number and connects directly to the IP.

Propagation

When you buy a domain name and change its settings, it can take up to 48 hours to "propagate." This is because millions of DNS servers around the world have cached the old IP address and need to wait for that cache to expire before asking for the new one.