the internet

oct10-ip.md

@@ -2,7 +2,7 @@
 
 ## Overview
 
-- IP
+- IP: v4 and v6
     - Class A, B, C, D
     - CIDR
 - Mask
@@ -12,7 +12,22 @@
     - ICMP (`ping`, traceroute)
     - UDP
     - TCP
+    - DNS
 - Commands
     - `host`
     - `nslookup`
     - `ifconfig`
+
+## The Internet
+
+There are multiple ways to get to where you want to go.
+
+1. A computer makes a request for some information from a location.
+2. The receiving end understands the request and sends the information back.
+
+When you call someone, you look them up in your contacts, when you go to
+`www.google.com`, your computer looks up its ip address in Domain Name System
+(DNS)
+
+An ip (v4) address is always in this format: XXX.XXX.XXX.XXX, for example,
+127.0.0.1