Exactlimon and Web 2.0

In computing, a port is a generic designation for an interface through which different types of data can be sent and received. This interface can be physical, or it may be a software (eg ports that enable the transmission of data between different computers) read more ..

complete list of ports and their uses. here

that the wise msn messenger connects via port 1853, and that for example in my university can not enter the blocked or closed because they have this port on the main server.