Nmap ZenMap Switches Practice Test

The main idea here is how an ACK scan works and what it can reveal about a firewall. The -sA option performs a TCP ACK scan, sending ACK packets to each port. Because ACKs aren’t used to open a connection, the target’s responses (or lack thereof) depend on the firewall’s rules rather than on whether a port is actually open. If a firewall is stateful, it tends to filter unsolicited ACKs and may drop them, producing no response for filtered ports; if a firewall is stateless, you’ll see different, predictable responses for allowed versus blocked paths. By observing which ports elicit a RST or no response, you can map the firewall’s rule set and determine whether filtering is stateful or stateless. This doesn’t indicate open ports, which is why this scan is specifically about firewall behavior rather than port openness.