All ports
Port399/TCP
iso-tsap-c2Port
399
Protocol
TCP
Category
Well-Known
Service
iso-tsap-c2
What is port 399?
Port 399/TCP is a Well-Known port, assigned by IANA for widely recognized services. It is associated with the iso-tsap-c2 service.
ISO Transport Class 2 Non-Control over TCP
Useful commands
nmapnmap -p 399 -sV example.comnetcatnc -zv example.com 399curlcurl -v http://example.com:399/telnettelnet example.com 399bash(echo > /dev/tcp/example.com/399) 2>/dev/nullFirewall commands
UFWAllow
sudo ufw allow 399/tcpDeny
sudo ufw deny 399/tcpiptablesAllow
sudo iptables -A INPUT -p tcp --dport 399 -j ACCEPTDeny
sudo iptables -D INPUT -p tcp --dport 399 -j ACCEPTfirewalldAllow
sudo firewall-cmd --permanent --add-port=399/tcpWindowsAllow
netsh advfirewall firewall add rule name="Open Port 399" dir=in action=allow protocol=TCP localport=399Security 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- Outdated versions with vulnerabilities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 399/TCP?
Port 399/TCP is associated with the iso-tsap-c2 service. ISO Transport Class 2 Non-Control over TCP
Is it safe to expose port 399 to the Internet?
It depends on the service and configuration. Port 399 (iso-tsap-c2) 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 399 is open?
You can use nmap: `nmap -p 399 -sV example.com`, netcat: `nc -zv example.com 399`, or the bash command: `(echo > /dev/tcp/example.com/399) 2>/dev/null && echo "Open" || echo "Closed"`.
How do I open or close port 399 on my firewall?
On Linux with UFW: `sudo ufw allow 399/tcp` (open) or `sudo ufw deny 399/tcp` (close). With iptables: `sudo iptables -A INPUT -p tcp --dport 399 -j ACCEPT`. On Windows: `netsh advfirewall firewall add rule name="Open Port 399" dir=in action=allow protocol=TCP localport=399`.
What applications and services use port 399?
Port 399/TCP is used by the iso-tsap-c2 service. Specific uses depend on the software and configuration. Check our related tools section for more information.