Port Scanning Techniques CEH Practice Questions (Page 3)

Questions 11–15

1. 11application · medium

   A network administrator is troubleshooting a service that is not responding. The administrator runs an Nmap SYN scan against the server and receives no response for a specific TCP port, while other ports respond with RST. What is the most likely state of that specific port?

   • AUnfiltered
   • BClosed
   • CFiltered
   • DOpen
   Reveal Solution Discussion Select an answer first
2. 12foundation · easy

   In Nmap, what is the purpose of using the -D option to specify decoy addresses?

   • ATo fragment the scan packets into smaller pieces to evade firewalls.
   • BTo hide the real source IP by making it appear that multiple hosts are scanning the target.
   • CTo use a zombie host to bounce the scan and hide the scanner's identity.
   • DTo randomize the order of ports scanned to avoid detection.
   Reveal Solution Discussion Select an answer first
4. 13foundation · easy

   What is a common countermeasure to prevent port scanning from revealing open services on a host?

   • AConfiguring a firewall to block or filter unsolicited inbound traffic.
   • BChanging the host's IP address frequently.
   • CUsing a proxy server for all outbound traffic.
   • DDisabling the host's network interface when not in use.
   Reveal Solution Discussion Select an answer first
5. 14foundation · easy

   During the information gathering phase, why is port scanning considered a valuable technique for an ethical hacker?

   • AIt helps identify live hosts and the services they run, which can be probed for vulnerabilities.
   • BIt allows the tester to bypass authentication mechanisms on the target's web application.
   • CIt provides a map of the target's network topology, including routers and switches.
   • DIt reveals the target's public IP address and DNS records.
   Reveal Solution Discussion Select an answer first
6. 15foundation · easy

   After running an Nmap scan, you see the following output for a port: '80/tcp open http'. What does the 'open' state indicate?

   • AThe port is accessible and a service is actively accepting connections.
   • BThe port is open but the service is not responding to probes.
   • CThe port is closed but the firewall is allowing packets through.
   • DThe port is filtered by a firewall and no response is received.
   Reveal Solution Discussion Select an answer first