All ports
Port1921/TCP
noadminPort
1921
Protocol
TCP
Category
Registered
Service
noadmin
What is port 1921?
Port 1921/TCP is a Registered port, registered with IANA for specific applications. It is associated with the noadmin service.
NoAdmin
Useful commands
nmapnmap -p 1921 -sV example.comnetcatnc -zv example.com 1921curlcurl -v http://example.com:1921/telnettelnet example.com 1921bash(echo > /dev/tcp/example.com/1921) 2>/dev/nullFirewall commands
UFWAllow
sudo ufw allow 1921/tcpDeny
sudo ufw deny 1921/tcpiptablesAllow
sudo iptables -A INPUT -p tcp --dport 1921 -j ACCEPTDeny
sudo iptables -D INPUT -p tcp --dport 1921 -j ACCEPTfirewalldAllow
sudo firewall-cmd --permanent --add-port=1921/tcpWindowsAllow
netsh advfirewall firewall add rule name="Open Port 1921" dir=in action=allow protocol=TCP localport=1921Security 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- Outdated versions with vulnerabilities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 1921/TCP?
Port 1921/TCP is associated with the noadmin service. NoAdmin
Is it safe to expose port 1921 to the Internet?
It depends on the service and configuration. Port 1921 (noadmin) 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 1921 is open?
You can use nmap: `nmap -p 1921 -sV example.com`, netcat: `nc -zv example.com 1921`, or the bash command: `(echo > /dev/tcp/example.com/1921) 2>/dev/null && echo "Open" || echo "Closed"`.
How do I open or close port 1921 on my firewall?
On Linux with UFW: `sudo ufw allow 1921/tcp` (open) or `sudo ufw deny 1921/tcp` (close). With iptables: `sudo iptables -A INPUT -p tcp --dport 1921 -j ACCEPT`. On Windows: `netsh advfirewall firewall add rule name="Open Port 1921" dir=in action=allow protocol=TCP localport=1921`.
What applications and services use port 1921?
Port 1921/TCP is used by the noadmin service. Specific uses depend on the software and configuration. Check our related tools section for more information.