← Port Encyclopedia
503

Port-503

TCP
System Low Risk
Reserved or unassigned port 503 — may appear in network scans as open, closed, or filtered

🔍 How to Scan Port 503

nmap -sV -p 503 target
nmap -sV -sC --script=banner -p 503 target
nc -zv target 503

🛡️ Security Considerations

  • Scan port 503 with nmap -sV to identify the exact service and version
  • If Port-503 is not needed, close or firewall this port immediately
  • Check for default credentials if a management interface runs on this port
  • Use searchsploit port-503 to find known exploits
  • Monitor traffic on port 503 with Wireshark or tcpdump for anomalies
  • Ensure the service is patched to the latest version to prevent known CVE exploitation

🔗 Related System Ports

Port 1
TCPMUX
Port 5
RJE
Port 7
Echo
Port 9
Discard
Port 11
systat
Port 13
Daytime
Port 17
QOTD
Port 19
Chargen
Port 37
Time
Port 79
Finger
Port 111
RPCbind
Port 113
Ident

📍 Nearby Ports

Port 498
Port-498
Port 499
Port-499
Port 500
IKE
Port 501
Port-501
Port 502
Modbus
Port 504
Port-504
Port 505
Port-505
Port 506
Port-506
Port 507
Port-507
Port 508
Port-508
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