

Port 500 for Internet Security Association and Key Management Protocol (ISAKMP).Port 445 for Server Message Block (SMB).Port 161 for Simple Network Management Protocol (SNMP).

Port 143 for Internet Message Access Protocol (IMAP).Port 123 for Network Time Protocol (NTP).Port 110 for Post Office Protocol, version 3 (POP3).Port 80 for Hypertext Transfer Protocol (HTTP).Port 25 for Simple Mail Transfer Protocol (SMTP).Ports 20 and 21 for File Transfer Protocol (FTP).

But some widely used ports and their associated networking protocols are TCP and UDP headers indicate the port number to which network traffic is forwarded. The IP(Internet Protocol) address enables network communication on a specific device, and the port numbers specify the particular service to target on those devices. For example, all Hypertext Transfer Protocol (HTTP) messages go to port 80. Mostly each port is reserved for serving a specific protocol.
FREE PORT FORWARDING TOOLS SOFTWARE
We can recognize it as a logical construct used to specify a network service or a particular function at the software level. Each port is associated with a specific service or process. Ports are software-based and managed by the computer's operating system. It is the virtual point where the network connection starts and ends. Port is a term used in computer networking. About Online Port Scanning - Discover Open TCP & UDP Ports What is a Port?.
