Port Numbers In Computer Networking

Good day, tech enthusiasts! Today, I will be writing about ports, as used in computer networking. I have just learnt about this important topic and I will not hesitate to share it with you. The role of ports is very significant in computer networking. Two or more devices cannot communicate with one another without ports. Let's get started by knowing what ports actually are.

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Ports are used in computer networking. They are used to distinguish the beginning and end of a connection. Each port is associated with a particular service or a process and directs data to the service or process. Ports are represented by port numbers. For instance, we have ports 80, 21, 443 and so on. A port number is assigned to each transfer protocol. Ports are also associated with the host's IP address.

The port numbers range from 0 to 65535. For instance, in most of the protocols, port number 0 is reserved. For instance, in TCP, port 0 cannot be used. Also in UDP, port number 0 is reserved as optional, so if the port number is set to 0, it means no port at all. Where port numbers 1 to 1024 are dedicated to the most common protocols like HTTP, FTP,SSH and others. In data communication, processes are associated with the input and output channels through something called internet sockets. They are file descriptors that contain the internet protocol, the IP address, and the port number .

A process is able to send and receive data only through the sockets that contain the port number. The software in the OS that manages networking has the task of conveying all outgoing messages from the various application ports on the system onto the network. For instance, if you are communicating via the internet with HTTP , the process will be associated with the port responsible for HTTP data transfer( port 80), and the networking software will then have to transmit the data you are conveying onto the internet through the port. There would be a port conflict if several processes attempted to use the same port number on the same IP address.

Some of the Most Used Port Numbers and their Assignments

Port Number	Sevice
80	HTTP, used in World Wide Web
443	HTTPs, Secured HTTP
546/547	DHCPv6
20	FTP, for File transfer
21	FTP, command Control
22	SSH, Secure Login
23	Telnet
25	SMTP, for email delivery
110	Post Office Protocol(POP3)
67,68	DHCP

Port numbers are very important in data networking. For developers, you can send a POST or GET request to a particular transfer protocol by listening to the port number of the protocol. Also, to create a local server, developers usually use higher port numbers because, as I indicated earlier, the lower port numbers(from 1 to 1024) are reserved for most of the common protocols, including those listed in the table above. Thanks for your time

Yours @salamdeen