Video Description

Application Layer- Web Services

  • HTTP

    • Hyper Text Transfer Protocol
    • Supports web services
    • Uses port number 80
    • The secure version is HTTPS
    • HTTPS uses port number 443
    • Transfers text, images, and hyper links
  • HTTPS
  • File Sharing Services/File transfer

    • FTP

      • File Transfer Protocol
      • Uses port number 21
      • Built=in in MS Windows Operating Systems
      • Many 3rd party programs
      • Web browser works as FTP client
    • TFTP
    • Network File System
  • Mail Services

    • SMTP

      • Common language used by the majority of mail servers
      • Send messages back and forth to other mail servers or email clients
    • POP3 "Post Office Protocol version 3"

      • Collects email messages from the mail server
      • Download messages on the machine
      • User can work offline
      • Saves quota on the server
    • IMAP4 "Internet Message Access Protocol version 4"

      • Retrieves the message header only
  • DNS Services

    • Domain Name System DNS resolves Domain Name into IP Address

Course Modules