Download notes and capture files here: http://willbradley.name/how-the-internet-works/

1. How the Internet
Works
From “www.google.com” onwards
http://willbradley.name/how-the-internet-works
@willbradley
CactusCon 2014

2. Connections and Protocols
“7 Layer OSI
Model”
Mostly
theoretical.
Note:
ARP/MAC, IP,
TCP, DNS, H
TTP.

3. Packets (in Wireshark)

4. DNS Lookups
Recursion!
Root: .
TLD: .org.
NS: heatsynclabs.org.
IP: 72.44.240.228

5. Subnets and Masks
Binary!
Addresses “in”
this network start
with “011”:
95: 0101 1111
96: 0110 0000
97: 0110 0001
98: 0110 0010
…
100: 0110 0100
…
124: 0111 1100
125: 0111 1101
126: 0111 1110
127: 0111 1111
128: 1000 0000

6. NAT (actually PAT)

7. Real Routing (BGP!)

8. Port Forwarding / Firewalls

9. Ethernet (100 BASE T)

10. Subnetting Issues

11. DNS Cache Poisoning

12. Switching and Broadcast Storms

13. ARP Spoofing / MITM