IP Addresses

ifconfig : Unix command for get ips (ip addr or ip -c -br a)

On layer 3 of OSI format → router

ipv4 addresses : 4 * 1 byte → 255.255.255.255 → 2^32 (4*8) possible addresses ⇒ not enough

ipv6 addresses : 2^256 (je suis nul en math 😟  mais c’est bcp, plus que necessaire a priori)

Private ip address

Class A : large corporation, less network, more host

Class C : home size, 254 hosts

Mac address

layer 2 → switchs

physical address, know what is what, communicate around switchs

identifiers → 3 pairs = identifiers

lookup mac address → know the material

TCP - UDP - Three way handshake

TCP - High reliability

UDP - Streaming, connectionless

Scan both but more TCP

TCP