Nmap Basic Port Scans

Prompts and answers

• Which service uses UDP port 53 by default?
  DNS
• Which service uses TCP port 22 by default?
  SSH
• How many port states does Nmap consider?
  6
• Which port state is the most interesting to discover as a pentester?
  Open
• What 3 letters represent the Reset flag?
  RST
• Which flag needs to be set when you initiate a TCP connection (first packet of TCP 3-way handshake)?
  SYN
• Launch the VM. Open the AttackBox and execute nmap -sT MACHINE_IP via the terminal. A new service has been installed on this VM since our last scan. Which port number was closed in the scan above but is now open on this target VM?
  110
• What is Nmap’s guess about the newly installed service?
  POP3
• Launch the VM. Some new server software has been installed since the last time we scanned it. On the AttackBox, use the terminal to execute nmap -sS MACHINE_IP. What is the new open port?
  6667
• What is Nmap’s guess of the service name?
  IRC
• Launch the VM. On the AttackBox, use the terminal to execute nmap -sU -F -v MACHINE_IP. A new service has been installed since the last scan. What is the UDP port that is now open?
  53
• What is the service name according to Nmap?
  domain
• What is the option to scan all the TCP ports between 5000 and 5500?
  -p5000-5500
• How can you ensure that Nmap will run at least 64 probes in parallel?
  --min-parallelism=64
• What option would you add to make Nmap very slow and paranoid?
  -T0