OSI 7 Layres

  • Application Layer (Layer 7)
    • HTTP, HTTPS
    • L7 firewall
  • Presentation Layer (Layer 6)
  • Session Layer (Layer 5)
    • Sessions
  • Transport Layer (Layer 4)
    • TCP, UDP, SCTP, TLS
  • Network Layer (Layer 3)
    • IP Address
    • Router, Layer 3 Switch
  • Data Link Layer (Layer 2)
    • Ethernet, 802.11(Wi-Fi), MAC Address
    • Layer 2 Switch
  • Physical Layer (Layer 1)
    • Hub, Wire, Fiber, Radio

TCP/IP protocols

  • HTTP
    • Hyper Text Transport Protocol
    • TCP Port 80
  • HTTPS
    • Hyper Text Transport Protocol Secure
    • TCP Port 443
  • FTP
    • File Transfer Protocol
    • TCP Port 21
  • Telnet
    • Telecommunication Protocol
    • TCP Port 23
  • SMTP
    • Simple Mail Transfer Protocol
    • TCP port 25
    • For email
  • DNS
  • TFTP
    • Trivial File Transfer Protocol
    • UDP port 69
    • Not secure. Should only be used in private net.
  • RADIUS
    • Remote Authentication Dial-In User Service
    • UDP Port : 1812 (authentication) & 1813(accounting)
    • Code
      • Access-Request
      • Access-Accept
      • Access-Reject
      • Access-Challenge