Network Ports 5.2.3

Network Ports

  • Unique numbers assigned by the operating system for different types of network traffic.

  • Help direct information based on its type.

  • Some ports are reserved for common services (e.g., email, file transfer).

  • Ports can be unassigned when not in use; closed ports deny entry.

Port Forwarding

  • Instructing a router or firewall to redirect info packets to a new address.

  • Commonly associated with port 3389 for Remote Desktop Protocol (RDP).

  • Enables connection to Windows computers globally.

  • Requires correct setup on both computers and the router to function effectively.

Port Numbers and Protocols

  • 21: File Transfer Protocol (FTP)

    • Standard protocol for moving files between computers.

  • 22: Secure Shell (SSH)

    • Provides secure communication between devices.

  • 23: Telnet

    • Provides unsecure communication between devices.

  • 25: Simple Mail Transfer Protocol (SMTP)

    • Used for sending email (deprecated in the last decade).

  • 53: Domain Name System (DNS)

    • Translates friendly domain names to IP addresses.

  • 80: Hypertext Transfer Protocol (HTTP)

    • Communication standard for clients and servers on the World Wide Web.

  • 110: Post Office Protocol version 3 (POP3)

    • Used by email programs for incoming mail.

  • 143: Internet Message Access Protocol (IMAP)

    • Most commonly used for receiving mail.

  • 443: Hypertext Transfer Protocol Secure (HTTPS)

    • Establishes encrypted communication between clients and servers on the World Wide Web.

  • 587: Simple Mail Transfer Protocol (SMTP)

    • Used for outgoing mail.