The above use of the terms "open" and "closed" can sometimes be misleading, though; it blurs the distinction between a given port being reachable (unfiltered) and whether there is an application actually listening on that port. Technically, a given port being "open" (in this context, reachable) is not enough for a communication channel to be established.
The use of "open" and "closed" can sometimes be misleading, though; it blurs the distinction between a given port being accessible (unfiltered) and whether an application is actively listening on that port. Technically, a given port being "open" (in this context, reachable) is not sufficient for a communication channel to be established.