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# What Exactly Is a Computer Port, What Can Be Found There, and How to See All Existing Ports of a Computer?

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A Computer Port Defined

A computer port is a physical or virtual interface that enables data to flow between a computer and external devices, or between software applications and network connections. They are essential for communication and connectivity.

What Exactly Is a Computer Port?

Computer ports can be understood from two primary contexts:

  1. Physical ports (hardware)
  2. Virtual/logical ports (software networking)

Physical Ports (Hardware)

These are the physical sockets on the computer's casing where you plug in cables and devices. They provide a standardized mode of connection to peripherals like monitors, keyboards, mice, printers, and external hard drives. Examples include USB, HDMI, Ethernet, and audio jacks.

Virtual/Logical Ports (Software/Networking)

These are not physical sockets but numerical identifiers (ranging from 0 to 65,535) used by networking protocols, e.g., TCP, UDP, and so on, to direct data to the correct software application on a computer.

For example:

  • Web browsers typically use port 80 or 443, which is part of the 65,535 numerical identifiers, for web traffic.
  • Email clients use ports like 25 or 110 to direct network traffic of specific email protocols like SMTP, POP3, or IMAP.

What Could Be Found There?

At a Physical Port

You can find:

  • The connection point itself
  • The cable connector that plugs into it (e.g., a USB-C cable or HDMI)
  • The peripheral device attached to it (e.g., a monitor, printer, or external drive)

The port provides an interface for data transfer and sometimes power delivery.

At a Virtual/Logical Port

You find the data stream associated with a specific running application or network service.

The port number acts as a “mailing address” to ensure that incoming network traffic reaches the correct program.

Examples:

  • Data arriving on port 22 is directed to the Secure Shell (SSH) service.
  • Data on port 3389 goes to the Remote Desktop Protocol (RDP) service.

How to See All the Ports?

To See Physical Ports

Simply look at the front, back, and sides of your desktop computer, laptop, or other device.

Those holes are ports. You will visibly see the different shapes and types of connectors.

To See Virtual/Logical Ports

You need to use command-line tools within your operating system. These tools display which ports are open, listening for connections, and which applications are using them.

Windows

Open the Command Prompt or PowerShell and type:

netstat -ano
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This command lists all active connections and listening ports, along with the Process ID (PID) of the application using them.

macOS and Linux

Use any of these commands in the Terminal:

netstat -tuln
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ss -tuln
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lsof -i
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In Conclusion

You can see the physical ports directly, but you cannot directly see the virtual/logical ports except by using command-line tools that depend on the operating system you are using.

However, you should use your understanding of how the physical ports work to grasp the idea behind the virtual version. Just as you need cables to connect your peripherals like a monitor or mouse, you need virtual ports to connect two machines wirelessly, and those ports are numbered from 1 to 65,535.

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