All ports
Port9909/UDP
domaintimePort
9909
Protocol
UDP
Category
Registered
Service
domaintime
What is port 9909?
Port 9909/UDP is a Registered port, registered with IANA for specific applications. It is associated with the domaintime service.
domaintime
Useful commands
nmapnmap -p 9909 -sV example.comnetcatnc -zv example.com 9909curlcurl -v http://example.com:9909/telnettelnet example.com 9909bash(echo > /dev/udp/example.com/9909) 2>/dev/nullFirewall commands
UFWAllow
sudo ufw allow 9909/udpDeny
sudo ufw deny 9909/udpiptablesAllow
sudo iptables -A INPUT -p udp --dport 9909 -j ACCEPTDeny
sudo iptables -D INPUT -p udp --dport 9909 -j ACCEPTfirewalldAllow
sudo firewall-cmd --permanent --add-port=9909/udpWindowsAllow
netsh advfirewall firewall add rule name="Open Port 9909" dir=in action=allow protocol=UDP localport=9909Security Risks
- DNS cache poisoning attacks
- DDoS amplification using open DNS resolvers
- Information disclosure of internal subdomains
- Domain hijacking if DNS server is misconfigured
Frequently Asked Questions
What service runs on port 9909/UDP?
Port 9909/UDP is associated with the domaintime service. domaintime
Is it safe to expose port 9909 to the Internet?
It depends on the service and configuration. Port 9909 (domaintime) is a Registered 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 9909 is open?
You can use nmap: `nmap -p 9909 -sV example.com`, netcat: `nc -zv example.com 9909`, or the bash command: `(echo > /dev/udp/example.com/9909) 2>/dev/null && echo "Open" || echo "Closed"`.
How do I open or close port 9909 on my firewall?
On Linux with UFW: `sudo ufw allow 9909/udp` (open) or `sudo ufw deny 9909/udp` (close). With iptables: `sudo iptables -A INPUT -p udp --dport 9909 -j ACCEPT`. On Windows: `netsh advfirewall firewall add rule name="Open Port 9909" dir=in action=allow protocol=UDP localport=9909`.
What applications and services use port 9909?
Port 9909/UDP is used by the domaintime service. Specific uses depend on the software and configuration. Check our related tools section for more information.