Continuation with network layers

Lab 5 is due soon

TCP/IP ModelPacket UnitsAcronym
ApplicationDataDon’t
TransportSegmentSmoke
NetworkPacketPot
DataLinkFramesFrom
PhysicalBitsBongs

TCP Connection Setup (3 Way Handshake)

Client –> Server SYN Server –> Client SYN + ACK Client –> Server SYN Server –> Client

Application Layer Protocols

  • DNS
  • HTTP
  • Email
  • SSH
  • FTP

Network Address Translation

  • Basic NAT
    • Translates one IP address into another
  • Port Address Translation
    • Allows multiple hosts to use a single public IP address
  • Static and Dynamic
    • NAT provides dynamic IP address for each host
  • Benefits
    • No need to find an open IP addresses. Allows sharing
    • Provides some security. As device IPs are constantly switching, an attacker can’t only rely on an IP address to attack a specific client.