If your computer is connected to the Internet is intermittent, will make its global connectivity, for example, include a modem and running the service his program. Also pre-start the browser or the program you wish to connect to the server for an unknown port. Try typing in your browser the website address: if then it automatically adds a colon and the port number, no further action is possible not to carry out - it becomes known to you.
Open the console. In the Linux operating system run the program rxvt, xterm or Konsole. In Windows, use cmd (start - Run - type cmd - OK).
When the console opens, start the process of connecting the programs that interest you to the Internet or start the update in the browser the pages you like, and then immediately (while the connection is not closed), type the console command netstat-ano (to a minus gap is followed by not).
The screen will display two tables. Please note the column "Foreign address" (or Foreign Address) the first of these tables. It lists the IP address, after each of which a colon is specified port. Usually it has the number 80, which is open from all providers. If you see other ports, please call the support provider, name your rate, and ask whether you are open for these ports. You can also specify the corresponding password in the support forum provider. If you find that the ports are closed, if possible reconfigure the program so that it connects to the server on a different port. View the same content on the page using the Opera Turbo service, Skweezer or similar. In a pinch, go to a more expensive tariff after learning that will then open the port you want. Be aware that opening a few ports poses a security risk to the system.