All ports
Port121/UDP
erpcPort
121
Protocol
UDP
Category
Well-Known
Service
erpc
What is port 121?
Port 121/UDP is a Well-Known port, assigned by IANA for widely recognized services. It is associated with the erpc service.
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Useful commands
nmapnmap -p 121 -sV example.comnetcatnc -zv example.com 121curlcurl -v http://example.com:121/telnettelnet example.com 121bash(echo > /dev/udp/example.com/121) 2>/dev/nullFirewall commands
UFWAllow
sudo ufw allow 121/udpDeny
sudo ufw deny 121/udpiptablesAllow
sudo iptables -A INPUT -p udp --dport 121 -j ACCEPTDeny
sudo iptables -D INPUT -p udp --dport 121 -j ACCEPTfirewalldAllow
sudo firewall-cmd --permanent --add-port=121/udpWindowsAllow
netsh advfirewall firewall add rule name="Open Port 121" dir=in action=allow protocol=UDP localport=121Security Risks
- Unauthorized access to the service
- Data exposure if the service is unauthenticated
- Outdated versions with vulnerabilities
- Incorrect service configuration
Frequently Asked Questions
What service runs on port 121/UDP?
Port 121/UDP is associated with the erpc service. Encore Expedited Remote Pro.Call
Is it safe to expose port 121 to the Internet?
It depends on the service and configuration. Port 121 (erpc) is a Well-Known port. If you need to expose it, keep the service updated, use strong authentication, and configure a firewall. It's always recommended to restrict access by IP when possible.
How do I check if port 121 is open?
You can use nmap: `nmap -p 121 -sV example.com`, netcat: `nc -zv example.com 121`, or the bash command: `(echo > /dev/udp/example.com/121) 2>/dev/null && echo "Open" || echo "Closed"`.
How do I open or close port 121 on my firewall?
On Linux with UFW: `sudo ufw allow 121/udp` (open) or `sudo ufw deny 121/udp` (close). With iptables: `sudo iptables -A INPUT -p udp --dport 121 -j ACCEPT`. On Windows: `netsh advfirewall firewall add rule name="Open Port 121" dir=in action=allow protocol=UDP localport=121`.
What applications and services use port 121?
Port 121/UDP is used by the erpc service. Specific uses depend on the software and configuration. Check our related tools section for more information.