Open— The port is reachable and there is a service listening on it.Closed— The port is reachable and there is no service listening on it.Filtered— Nmap cannot determine the port state because the port is not accessible (probably because of a firewall).Unfiltered— Nmap cannot determine the port state, but the port is accessible (only encountered in ACK scans).Open|Filtered— Nmap can only determine that the port is not closed (only encountered in UDP scans and more exotic scans like Xmas).Closed|Filtered— Nmap can only determine that the port is not open (only encountered in IP ID idle scans).