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What does it mean if all ports are filtered?
Filtered means that a firewall, filter, or other network obstacle is blocking the port so that Nmap cannot tell whether it is open or closed. Closed ports have no application listening on them, though they could open up at any time.
Are filtered too many fingerprints match this host to give specific OS details?
“Too many fingerprints match this host to give specific OS details” means that the probes are contradictory or too broad. For example in a NAT scenario, some port scans return the router information (e.q. Cisco iOS), some other probes return the real host specifications (e.q. Windows).
Should ports be closed or filtered?
A closed port indicates that no application or service is not listening for connections on that port. A closed port can open up at any time if an application or service is started. A filter port indicates that a firewall, filter, or other network issue is blocking the port.
Why are some ports reported by Nmap filtered and not the open?
So Nmap does not know for sure whether the port is open or being filtered. The UDP, IP protocol, FIN, NULL, and Xmas scans classify ports this way. closed|filtered: This state is used when Nmap is unable to determine whether a port is closed or filtered.
Is there a way to see what is actually filtering TCP port?
If the TTL for a filtered port is different from (usually greater than) the TTL for open ports, then the difference between the TTLs is the network distance between the target and the filtering device.
Where are the ports filtered in a firewall?
Usually ports are filtered on the host it self (i.e. ip tables), target network edge router, target network core router or top of the rack L3 switch. If you are in the same subnet as target host almost for sure firewall is on target machine.
How to set up capture filters or display filters?
Shouldn’t be too difficult. One of the first things to know is how to set up capture filters or display filters, so as to filter the traffic to a single known MAC address, and eliminate the “background noise”.