The TCP ACK scanning technique uses packets with the flag ACK on to try to determine if a port is filtered. This technique comes handy when checking if the firewall protecting a host is stateful or stateless.
See Also
GRC | Port Status Info TCP flags - GeeksforGeeksTCP Connect Scan (-sT) | Nmap Network ScanningWhat is SYN scanning and how does it work?This recipe shows how to perform TCP ACK port scanning by using Nmap.
How to do it...
Open your terminal and type the following command:
#nmap -sA <target>
The output follows the standard port format:
# nmap -sA 192.168.1.254Nmap scan report for 192.168.1.254Host is up (0.024s latency).All 1000 scanned ports on 192.168.1.254 are unfilteredMAC Address: 5C:4C:A9:F2:DC:7C (Huawei Device Co.)
How it works...
The argument -sA tells Nmap to launch a TCP ACK port scan against the target host. ...
