← Port Encyclopedia
321
Port-321
TCP
System Low Risk
Reserved or unassigned port 321 — may appear in network scans as open, closed, or filtered

🔍 How to Scan Port 321

nmap -sV -p 321 target
nmap -sV -sC --script=banner -p 321 target
nc -zv target 321

🛡️ Security Considerations

  • Scan port 321 with nmap -sV to identify the exact service and version
  • If Port-321 is not needed, close or firewall this port immediately
  • Check for default credentials if a management interface runs on this port
  • Use searchsploit port-321 to find known exploits
  • Monitor traffic on port 321 with Wireshark or tcpdump for anomalies
  • Ensure the service is patched to the latest version to prevent known CVE exploitation