Port scanning with Nmap?

Question

Computer networks

When scanning ports on an IP address, Nmap determines that a specific port is open. At the same time, if you disable the Ethernet port on the switch, Nmap still displays information that this port is open. How does Nmap determine this if there is no physical signal to the device itself, because Nmap displays information about open ports in real time. Or does the utility save this information to something? If it retains this information, then for how long? And can this value be changed?

Answer 1

nmap does not save information about open ports and rescans each time it is started. If I were you, I'd make sure you're actually disabling the ethernet port behind which the IP (or IP range if you're scanning a range) is set to be scanned by nmap.
in general, the question gives the impression that you think that nmap is scanning the ehternet ports of the switch. this is not true; ports of udp and tcp protocols are scanned.

Answer 2

From the description it is not clear what network scheme. Perhaps you disable the port through which the switch is connected to the server, but port 22 is open on the switch itself.
Send more detailed technical information, it will be clearer.