What Is a Port Number and Why Is It Needed?

Communication on the internet is done through connections, which are identified by the ports. An IP address port number is needed to determine what network package to send to a particular server and what port is connecting to it. This means that knowing the number for a server allows us to establish which connection we are talking about.

A port number is simply an integer between 1 and 65535. Port numbers are allocated by the Internet Assigned Numbers Authority (IANA) for specific purposes like running a web server, sending an email, or using file transfer protocol (FTP).

Port numbers are becoming increasingly important because they are used to determine which program should receive incoming requests. Many people may also be wondering how to find port numbers or why they are needed. Internet users need to know what number their programs use to communicate with each other. In this article, we will tell you in detail what port numbers are.


TCP/IP Protocol:

The TCP/IP protocol was developed by DARPA in the 1970s and is still one of the most commonly used protocols in computer networks today. Despite its age, it remains reliable and efficient.

It is a suite of communications protocols that includes link layer, internet layer, and transport layer specifications. The protocol suites are most often found on four-layer models such as the OSI model, which is what we use for this paper.

TCP/IP supports two types of ports: TCP & UDP.

TCP vs. UDP:

TCP stands for Transmission Control Protocol, and in UDP, it stands for User Datagram Protocol. These two protocols are the same, but they use different methods of sending data packets.

The TCP protocol, which is slower than UDP, does reliable by checking with the receiver to confirm that all packets have been received.

UDP does not do this and instead relies on the sender to verify all packets have been sent correctly.

What is a Server Port?

A web server port is a computer that has been configured to respond to HTTP requests and serve up pages. Web servers typically use ports to communicate between each other and with the outside world.

These ports can be used for many different things, such as sending an email or accepting connections from other computers. They are often associated with specific protocols, such as port 25, which is the standard port for SMTP, the protocol for transporting email messages. Typically, the default HTTP port for a web server is 80.


Types of Ports:

There are three types of ports, well-known (range from 0-1023), registered (range from 1024-49151), and private (range from 49152-65535). Well-known ports are associated with processes that are publicly available to the Internet, whereas private ports are for use by internal company services or programs.

How to Find Port Number?

Many people are looking for the easiest way to find the port number of their applications. Quite often, it can be quite challenging to pinpoint what this number might be, but there are ways to get it within seconds. Following are the steps you need to follow:


For Windows:

  • Click on the search box and type “cmd” to open Command Prompt.
  • Now, type “ipconfig” to find out more about the IP addresses. People may not see their public IP if the user is behind the router. You can check public IP by visiting what is my IP, and if you want to hide it while browsing the internet, then you need to use a VPN. We recommend people use VeePN as it is the best VPN for online safety and protection.
  • The final step is to enter “netstart-a” and it will take about 5-10 minutes before you will see port connections.


For Mac:

  • Click on the Apple icon and look for System Preferences.
  • Now, go to Network.
  • Choose the network and go to advanced settings.
  • Open Port Scan tab.
  • Type the IP address, and you are done.

Common Ports:


Ports Associated Networking Protocols
20 & 21 FTP for transferring files between client and server
22 Secure Shell for building secure network connections
25 SMTP for sending emails
53 DNS
123 Network Time Protocol
500 Internet Security Association and Key Management Protocol
3389 Remote Desktop Protocol


Port Number vs. IP Address:

The two most crucial pieces of information needed for connecting to a server are the server’s IP address and port number. The IP address is the numeric form that is used for routing data over internet protocols. A port number identifies a computer’s actual location on the network. The IP address is required to send data packets to the server, while the port number specifies what type of application will receive them.

Port numbers are assigned by the Internet Assigned Numbers Authority (IANA) and can be seen as identifiers for different applications on a computer. For example, the standard HTTP web browser port number is 80, whereas SSH uses 22.