Network

4 networking layers

link layer: physical media

direction connections between machinespacket-based

internet layer

who do I want to talk to?

Internet Protocol (IP) address

IPv4 (32-bit) and IPv6 (128-bit)

how do I get messages to/from them?

route

ifconfig netstat -rn traceroute www.google.com

transport layer

reliable communication

transmission control protocol (TCP)

packets in sequence order and feedback of recieving packets

user datagram protocol (UDP, simpler but less reliable)

application layer

ftp, ssh

dns: domain name service

name registrars, dns registrar nslookup www.google.com

http: hypertext transfer protocol

telnet apache.org 80

https: http secure