All ports
Port9/UDP
discardPort
9
Protocol
UDP
Category
Well-Known
Service
discard
What is port 9?
Port 9/UDP is a Well-Known port, assigned by IANA for widely recognized services. It is associated with the discard service.
Discard
Useful commands
nmapnmap -p 9 -sV example.comnetcatnc -zv example.com 9curlcurl -v http://example.com:9/telnettelnet example.com 9bash(echo > /dev/udp/example.com/9) 2>/dev/nullFirewall commands
UFWAllow
sudo ufw allow 9/udpDeny
sudo ufw deny 9/udpiptablesAllow
sudo iptables -A INPUT -p udp --dport 9 -j ACCEPTDeny
sudo iptables -D INPUT -p udp --dport 9 -j ACCEPTfirewalldAllow
sudo firewall-cmd --permanent --add-port=9/udpWindowsAllow
netsh advfirewall firewall add rule name="Open Port 9" dir=in action=allow protocol=UDP localport=9Security 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- Outdated versions with vulnerabilities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 9/UDP?
Port 9/UDP is associated with the discard service. Discard
Is it safe to expose port 9 to the Internet?
It depends on the service and configuration. Port 9 (discard) 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 9 is open?
You can use nmap: `nmap -p 9 -sV example.com`, netcat: `nc -zv example.com 9`, or the bash command: `(echo > /dev/udp/example.com/9) 2>/dev/null && echo "Open" || echo "Closed"`.
How do I open or close port 9 on my firewall?
On Linux with UFW: `sudo ufw allow 9/udp` (open) or `sudo ufw deny 9/udp` (close). With iptables: `sudo iptables -A INPUT -p udp --dport 9 -j ACCEPT`. On Windows: `netsh advfirewall firewall add rule name="Open Port 9" dir=in action=allow protocol=UDP localport=9`.
What applications and services use port 9?
Port 9/UDP is used by the discard service. Specific uses depend on the software and configuration. Check our related tools section for more information.