An open FTP server port for uploading and downloading.
Port 22 is the SSH port. It is used to remotely connect to Linux servers in CLI mode.
SMTP server's open port for sending emails.
This port is used for web services such as IIS, Apache, and Nginx to provide external access.
Port 110 is open for the POP3 (email protocol 3) service.
137, 138, 139
Ports 137 and 138 are UDP ports for transferring files via My Network Places.
Port 139: connections over port 139 attempt to access the NetBIOS/SMB service. This protocol is used for file and printer sharing on Windows and SAMBA.
Port 143 is mainly used for Internet Message Access Protocol (IMAP) v2, a protocol for receiving emails akin to POP3.
Web browsing port. This is another type of HTTP that provides encryption and transmission over secure ports.
Port 1433 is the default port for SQL Server. The SQL Server service uses two ports: TCP-1433 and UDP-1434. Port 1433 is used for SQL Server to provide external services, while port 1434 is used to respond to the requester which TCP/IP port is used by SQL Server.
Port 3306, the default port for MySQL databases, is used by MySQL to provide external services.
Windows Server Remote Desktop Services
Port 3389 is the service port for the Windows Server remote desktop, through which you can connect to a remote server by using the "Remote Desktop" connection tool.
Similar to port 80, port 8080 is used for WWW proxy service for web browsing. Port number ":8080" is often appended to the URL when the user visits a website or uses a proxy server. In addition, port 8080 is the default service port after the Apache Tomcat web server is installed.