nMap port definitions

[RontheCrypto]

Hi All,

Please help me with question 100 of practice test domain 6. Official practice tests Version 4.

In the answers, the filtered and closed are reversed.

According to me, the definitions are as below:

OPEN: The port is accessible on the remote system, and an application is accepting connections on that port.;

FILTERED: The port is not accessible on the remote system.

CLOSED: The port is accessible on the remote system, but no application is accepting connections on that port

[dcontesti]

I do not have access to the questions that you refer to, so it is difficult to actually answer your question.

If this question is from (ISC)2 training materials, I suggest that you contact Exam Administration ( https://isc2.org/contact-us )

I have always used the following definitions

There are six states with nMAP.

1. Open: indicates that a service is listening on the specified port.
2. Closed: indicates that no service is listening on the specified port, although the port is accessible.  Accessible, means that it is reachable and is not blocked by a firewall or other security appliances/programs.
3. Filtered: means that Nmap cannot determine if the port is open or closed because the port is not accessible. 
4. Unfiltered: means that Nmap cannot determine if the port is open or closed, although the port is accessible. This state is encountered when using an ACK scan 
5. Open|Filtered: <eans that Nmap cannot determine whether the port is open or filtered.
6. Closed|Filtered: This means that Nmap cannot decide whether a port is closed or filtered.