When using a port monitor, I noticed that the states of some of the connections where categorized as "unknown". What does this mean?
I don't know how anyone could possibly answer this. You haven't explained what software you're using, which is the biggest key to this. The message "unknown" isn't magic, it was programmed by someone as a response to a certain result of application logic. What one program says is "unknown" would be what another program would refer to in different terms. Some answers are needed to questions like what are you using? What are you doing? How are you doing it?– WesleyDec 26, 2014 at 20:47
I'm using Cport from Nirsoft.– jaxDec 26, 2014 at 21:18
It means that the connection state is unknown.
Upon further information:
I'm using Cport from Nirsoft.
A quick check of their documentation says "items with unknown state (the state column is empty) are displayed." So my answer was actually more right than I realized. =) This means that no explicit state for the port is available. Probably meaning that it's not explicitly denying the connection attempt; it's just staying silent.
For further information you'd need to look through the source code, but since it's not open source you'll need to contact the vendor for deeper clarification.