All ports
Port433/TCP
nnspPort
433
Protocol
TCP
Category
Well-Known
Service
nnsp
What is port 433?
Port 433/TCP is a Well-Known port, assigned by IANA for widely recognized services. It is associated with the nnsp service.
NNTP for transit servers (NNSP)
Useful commands
nmapnmap -p 433 -sV example.comnetcatnc -zv example.com 433curlcurl -v http://example.com:433/telnettelnet example.com 433bash(echo > /dev/tcp/example.com/433) 2>/dev/nullFirewall commands
UFWAllow
sudo ufw allow 433/tcpDeny
sudo ufw deny 433/tcpiptablesAllow
sudo iptables -A INPUT -p tcp --dport 433 -j ACCEPTDeny
sudo iptables -D INPUT -p tcp --dport 433 -j ACCEPTfirewalldAllow
sudo firewall-cmd --permanent --add-port=433/tcpWindowsAllow
netsh advfirewall firewall add rule name="Open Port 433" dir=in action=allow protocol=TCP localport=433Security 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- Outdated versions with vulnerabilities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 433/TCP?
Port 433/TCP is associated with the nnsp service. NNTP for transit servers (NNSP)
Is it safe to expose port 433 to the Internet?
It depends on the service and configuration. Port 433 (nnsp) 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 433 is open?
You can use nmap: `nmap -p 433 -sV example.com`, netcat: `nc -zv example.com 433`, or the bash command: `(echo > /dev/tcp/example.com/433) 2>/dev/null && echo "Open" || echo "Closed"`.
How do I open or close port 433 on my firewall?
On Linux with UFW: `sudo ufw allow 433/tcp` (open) or `sudo ufw deny 433/tcp` (close). With iptables: `sudo iptables -A INPUT -p tcp --dport 433 -j ACCEPT`. On Windows: `netsh advfirewall firewall add rule name="Open Port 433" dir=in action=allow protocol=TCP localport=433`.
What applications and services use port 433?
Port 433/TCP is used by the nnsp service. Specific uses depend on the software and configuration. Check our related tools section for more information.