← Port Encyclopedia
121

Port-121

TCP
System Low Risk
Reserved or unassigned port 121 — may appear in network scans as open, closed, or filtered

🔍 How to Scan Port 121

nmap -sV -p 121 target
nmap -sV -sC --script=banner -p 121 target
nc -zv target 121

🛡️ Security Considerations

  • Scan port 121 with nmap -sV to identify the exact service and version
  • If Port-121 is not needed, close or firewall this port immediately
  • Check for default credentials if a management interface runs on this port
  • Use searchsploit port-121 to find known exploits
  • Monitor traffic on port 121 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 116
Port-116
Port 117
Port-117
Port 118
Port-118
Port 119
NNTP
Port 120
Port-120
Port 122
Port-122
Port 123
NTP
Port 124
Port-124
Port 125
Port-125
Port 126
Port-126
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