All ports
Port1821/TCP
donnyworldPort
1821
Protocol
TCP
Category
Registered
Service
donnyworld
What is port 1821?
Port 1821/TCP is a Registered port, registered with IANA for specific applications. It is associated with the donnyworld service.
donnyworld
Useful commands
nmapnmap -p 1821 -sV example.comnetcatnc -zv example.com 1821curlcurl -v http://example.com:1821/telnettelnet example.com 1821bash(echo > /dev/tcp/example.com/1821) 2>/dev/nullFirewall commands
UFWAllow
sudo ufw allow 1821/tcpDeny
sudo ufw deny 1821/tcpiptablesAllow
sudo iptables -A INPUT -p tcp --dport 1821 -j ACCEPTDeny
sudo iptables -D INPUT -p tcp --dport 1821 -j ACCEPTfirewalldAllow
sudo firewall-cmd --permanent --add-port=1821/tcpWindowsAllow
netsh advfirewall firewall add rule name="Open Port 1821" dir=in action=allow protocol=TCP localport=1821Security 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- Outdated versions with vulnerabilities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 1821/TCP?
Port 1821/TCP is associated with the donnyworld service. donnyworld
Is it safe to expose port 1821 to the Internet?
It depends on the service and configuration. Port 1821 (donnyworld) 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 1821 is open?
You can use nmap: `nmap -p 1821 -sV example.com`, netcat: `nc -zv example.com 1821`, or the bash command: `(echo > /dev/tcp/example.com/1821) 2>/dev/null && echo "Open" || echo "Closed"`.
How do I open or close port 1821 on my firewall?
On Linux with UFW: `sudo ufw allow 1821/tcp` (open) or `sudo ufw deny 1821/tcp` (close). With iptables: `sudo iptables -A INPUT -p tcp --dport 1821 -j ACCEPT`. On Windows: `netsh advfirewall firewall add rule name="Open Port 1821" dir=in action=allow protocol=TCP localport=1821`.
What applications and services use port 1821?
Port 1821/TCP is used by the donnyworld service. Specific uses depend on the software and configuration. Check our related tools section for more information.