What is Port?

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Virtual points where network connections begin and stop are called ports. Ports are software-based and controlled by operating system. Each port is connected to a different procedure or service. Ports allow computers to easily differentiate between different kinds of traffic: emails go to a different port number than webpages, for example, even though both reach a computer over the same Internet connection.

Port number is a 16-bit logical address that is assigned to every application of your device and used to transmit data between computer network and application.

Introduction to Port

A port is just like a physical docking point which is used to connect the external device to the computer. A Port can also be considered as a programmatic docking point by which information transmits from a program to the computer or over the Internet.

  • In a computer network, a Port is a logical address that is assigned to each application on the computer that utilizes the internet for communication.
  • Port is an address of a 16-bit unsigned integer number that ranges from 0 to 65535.
  • The primary application of a port number is to transmit the data between a Computer Network and an Application.
  • Port is just a unique number assigned to every application of a computer.
  • However, the operating system can automatically assign a port number to the application running on the computer.
  • Port allows the computer to differentiate between all coming traffic such as email going to different ports and web pages going to different ports.
  • After seeing what is the port number now let us see different ranges of port numbers.
  • The ports 0 to 1023 are called well-known ports or system ports, these ports are especially associated with particular services.
  • The ports from 1024 to 49151 are called registered ports and this range port can be registered with the Internet Assigned Numbers Authority for a specific use.
  • The ports from 49152 to 65535 are unassigned ports, called dynamic or ephemeral ports, and can be utilized for any type of service.

How Do Ports Work in Networking?

Port numbers in networking manage the multiple transmission requests by a single physical network on a computer. Port has two main applications in a computer network which are given below:

  • A Port number in networking is a software-defined number that is related to the transport layer and used to transmit communication for a specific service
  • When it is required to convert a piece of software to run on another device or operating system, then the port number is utilized as computer software.

What are Port Numbers in Networking?

Port is a concept of the transport layer of an OSI suite. Transport layer protocol such as UDP(User Datagram Protocol) and TCP(Transmission Control Protocol) has a section in their headers for indicating the port number. Network layer protocol such as IP protocol header only contains the destination IP address, not the port number.

What are the Different Port Numbers?

Port numbers in the networking range from 0 to 65535. The Internet Assigned Numbers Authority (IANA) is responsible for maintaining the list of Port numbers. Internet Assigned Numbers Authority (IANA) manages the network-related protocols. There are commonly used port numbers with their associated network protocol.

  • Ports 20 and 21: FTP stands for File Transfer Protocol and is used to transmit files between a client and a serve and uses port numbers 20 & 21.

  • Network Port 22: The Protocol Secure Shell (SSH) uses port number 22 and creates secure network connections.

  • Port 25: Simple Mail Transfer Protocol (SMTP) uses port number 25 and it is utilized in transmitting mail.

  • A Port 80: Hypertext Transfer Protocol (HTTP) is the protocol that allows accessing web pages over the World Wide Web and uses port number 80.

  • Port 123: Network Time Protocol (NTP) use port number 123 and allows the computer clocks to sync. This process is required for the encryption process.

  • Port 179: Border Gateway Protocol (BGP) utilizes port number 179 and it is required for establishing efficient routes among the extensive networks that make up the Internet.

  • Port 443 stands for HTTP Secure and it is the secure and encrypted version of HTTP. All HTTPS web traffic goes to port number 443.

  • Port 500: Internet Security Association and Key Management Protocol (ISAKMP) uses port number 500 and it is part of the process of configuring secure IPsec connections.

  • Port 3389: Remote Desktop Protocol (RDP) uses port number 3389 port number and it allows users to connect remotely to their desktop computers and another device.

Below is an image to show different well-known ports

different port numbers

How Do Ports Make Network Connections More Efficient?

  • As we all see varieties of data are transmitted to and from a computer over the same network.
  • The port numbers help the computer understand what to do with the data it receives.
  • Now let us understand it with an example Suppose there is a person named A and A who want to transfer an MP3 audio recording to person B using the File Transfer Protocol(FTP). And there is a person B, B's computer sends MP3 files data to B’s email application, but the email application does not know how to interpret the data. But A's used port number 21(FTP) for sending files so B's computer will able to store and receive files Meanwhile, B’s computer loads HTTP pages simultaneously using port number 80, even though both webpages data and MP3 files flow over the same network connection.

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  • In computer network port is a logical address of 16 bits which is assigned to every application running on your device that uses the internet for communication.
  • Port numbers are a concept of the 4th layer( Transport Layer ) of the OSI suite.
  • Port numbers in the networking range from 0 to 65535.
  • Port number 0 to 1023: Reserved Ports
  • Port number 1024 to 49151: Registered Ports
  • Port number 49151 to 65535: Dynamic ports
  • The Internet Assigned Numbers Authority (IANA) is an organization that maintains the list of all port numbers.