A computer port is a route through which all network connections start and end. A computer port is a way to manage all different types of communication that happen between different devices in a network.
A computer port is managed by the operating system of the devices. Port is used to differentiate between different traffic flows in a network like traffic of webpage, file sharing, email, etc.
Common port used in networking
Port 80
HTTP(HyperText Transfer Protocol) used port 80 to run a non-secure version of the World Wide Web. Port 80 is the default port used to send and receive unencrypted web pages.
Open port 80 on your system can be dangerous for your system to cyber-attack. But by closing port 80 you cannot ensure that your system is safe from cyber attack.
Port 443
HTTPS(HyperText Transfer Protocol Secure) used port 443 to run a secure version of the World Wide Web. HTTPS uses a secure and encrypted connection over HTTP protocol. HTTPS protocol helps devices download the webpage securely.
Port 443 is a standard port for sending and receiving secure HTTP traffic. When you browse the web if you see https before url and lock icon that means that the website is running on Port 443.
Port 20 and 21
Port 20 and 21 are used by FTP(File Transfer Protocol). It is made to establish a connection between two different devices. This Port is used to transfer files between a client and a server.
Port 21 is useful to send and receive commands immediately without waiting for the data transfer to finish.
Port 22
SSH(Secure Shell) used port 22 to create a secure network connection. It is designed to replace Telnet and FTP. Port 23 is used to access another computer in a secure environment
The SSH protocol has 3 layers i.e. Transport, authentication, and connection layer.
Port23
Port 23 is used by Telnet protocol. This Port is used to access the Unix server to run and make changes in programs.
Port 23 is not an encrypted protocol. If someone captures your traffic can easily see your credential information.
Port 25
SMTP(Simple Mail Transfer Protocol) uses port 25 to send emails from the user of one domain to the user of another domain. Port 25 provides a secure connection to send an email.
Port 53
DNS(Domain Name System) used port 53 for their work. DNS is used to convert the domain name into the IP address of that website or vice versa to help the system access that website.
Port 123
NTP(Network Time Protocol) uses port 123 to sync the time of the system according to the network. NTP syncs system time according to the timezone set by the user or by default.
Port 110 and 143
Both ports 110 and 143 are used to receive emails from other domain users. Port 110 is used by POP3 protocol and port 143 is used by IMAP4.
POP3 downloads email from the server and deletes that mail from the server. IMAP4 downloads emails from the server but doesn’t delete that mail from a server.
Port 3389
RDP( Remote Desktop Protocol) used port 3389 for its remote connectivity. RDP provides a remote connection to other user desktop computers.