CS338 Computer Security Monday, 4 April 2022 + Questions - Wireshark? - Anything else? + Selected computing history - Where does the money come from (war & commerce) - Babbage (1791-1871), Lovelace (1815-1852), logarithm & trig tables - Colossus (WWII), Turing, Bletchley Park, code-breaking - ENIAC (WWII), Mauchly & Echert et al, ballistics tables - ARPANET (1966-), (Advanced Research Projects Agency), Taylor/Kleinrock/Kahn/..., Cold War ballistic missle defense (DARPA = Defense Advanced Research Projects Agency) + Protocol stacks - TCP/IP - AppleTalk - XNS - Chaosnet - DECnet - SNA - ... - IP : Internet Protocol - what for? - route datagrams from source host to a destination host - "best-effort delivery" - details - IP address (v4 32 bits, X.Y.Z.W) (v6 129 bits, xyzw::abcd::...) - headers see a diagram (src and dest addresses, especially) - TCP - what for? - guarantees that packets will arrive - reassembly of packets into correct order - arrange for resending packets that get lost or corrupted - simulate "circuit switching" - TCP handshake - header - DNS - what for? - ...