All ports
Port33/UDP
dspPort
33
Protocol
UDP
Category
Well-Known
Service
dsp
What is port 33?
Port 33/UDP is a Well-Known port, assigned by IANA for widely recognized services. It is associated with the dsp service.
Display Support Protocol
Useful commands
nmapnmap -p 33 -sV example.comnetcatnc -zv example.com 33curlcurl -v http://example.com:33/telnettelnet example.com 33bash(echo > /dev/udp/example.com/33) 2>/dev/nullFirewall commands
UFWAllow
sudo ufw allow 33/udpDeny
sudo ufw deny 33/udpiptablesAllow
sudo iptables -A INPUT -p udp --dport 33 -j ACCEPTDeny
sudo iptables -D INPUT -p udp --dport 33 -j ACCEPTfirewalldAllow
sudo firewall-cmd --permanent --add-port=33/udpWindowsAllow
netsh advfirewall firewall add rule name="Open Port 33" dir=in action=allow protocol=UDP localport=33Security 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- Outdated versions with vulnerabilities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 33/UDP?
Port 33/UDP is associated with the dsp service. Display Support Protocol
Is it safe to expose port 33 to the Internet?
It depends on the service and configuration. Port 33 (dsp) 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 33 is open?
You can use nmap: `nmap -p 33 -sV example.com`, netcat: `nc -zv example.com 33`, or the bash command: `(echo > /dev/udp/example.com/33) 2>/dev/null && echo "Open" || echo "Closed"`.
How do I open or close port 33 on my firewall?
On Linux with UFW: `sudo ufw allow 33/udp` (open) or `sudo ufw deny 33/udp` (close). With iptables: `sudo iptables -A INPUT -p udp --dport 33 -j ACCEPT`. On Windows: `netsh advfirewall firewall add rule name="Open Port 33" dir=in action=allow protocol=UDP localport=33`.
What applications and services use port 33?
Port 33/UDP is used by the dsp service. Specific uses depend on the software and configuration. Check our related tools section for more information.