WellKnownPorts

Well-known ports are a set of standard port numbers used by network protocols and services for communication purposes. The Internet Assigned Numbers Authority (IANA) maintains a list of well-known ports, which are commonly used for various applications, including web servers, FTP servers, SMTP servers, and more.

The well-known ports are divided into three ranges:

* 0-1023: System ports, which are reserved for use by system processes and should not be used by applications

* 1024-49151: Registered ports, which are allocated for use by applications and services

* 49152-65535: Dynamic ports, which are available for use by applications and services

Some examples of well-known ports include:

* TCP port 80: Hypertext Transfer Protocol (HTTP) for web servers

* TCP port 21: File Transfer Protocol (FTP) for file transfers

* TCP port 25: Simple Mail Transfer Protocol (SMTP) for email servers

* TCP port 53: Domain Name System (DNS) protocol for domain name resolution

Using well-known ports can be beneficial for several reasons. First, it simplifies the process of setting up and connecting to services, as the port number is already well-established. Second, it helps to prevent potential security issues, as the port number is widely known and expected.

However, some ports are blocked by firewalls or security software for security purposes. In such cases, services may need to use an alternative port or configure the firewall to allow access to the well-known port.