This depends on the OS in use. In Windows, you can open a port by entering its port number through the 'Add port' function of Windows Firewall.
You can connect to an open port, for instance, 80 TCP port is a standard port for web pages.
You have to have a program that is actually using this port for it to be "open." As long as the program is not blocked by Windows Firewall, the port will be open.
go to your firewall and open port 3074.
TCP port 21
port filtering
Ports are somewhat like doors, traffic can flow either way though them but you can set them up so that it can only flow one way. A listening port is open and waiting for something to come in. It is possible to configure things so that a port can be used to receive traffic, but not send anything out through it. It is also possible to configure things so that a port is not listening but it is open for SENDING out information. Usually when we speak of an "open port" it is open for traffic both ways.
There is a shop at the port, and then there is a shop at the cafe itself right outside the port that is open. The actual restaurant part is not open yet.
The computer does not have to be connected to the internet at all for the port to be open, or listening.
mumbai
vizag
mumbai
The new one will open in 2013.