Here is a summary of topics
* The Internet protocol stack
  - 5 Layers
  - Examples of each
* HTTP
  - Request and response format
  - Non-persistent and persistent connections
  - Cookies
  - Caching
* DNS
  - Message format, record types
  - Root vs TLD vs authoritative vs local
  - Iterative vs recursive resolution
  - Attacks
* UDP
  - Header format, port numbers
  - Uses (streaming media, DNS, etc)
* TCP
  - Header format
  - Uses (HTTP, SMTP, etc)
  - Connection setup and teardown (3-way handshake)
  - Reliable data transfer (sequence & ack numbers, retransmits, etc)
* IP
  - Header format, IP addresses
  - Fragmentation
  - Mask (CIDR notation)
  - Longest-prefix matching
  - Link state routing (Dijkstra)
* Ethernet
  - Header format, MAC addresses
  - Behavior of a switch (fail open like a hub)
  - ARP
  - Day in Life
* Security
  - Crypto (symmetric vs public, RSA)
  - Firewall
  - Web attacks: XSS, SQLi, etc