All ports
Port4991/TCP
vrtPort
4991
Protocol
TCP
Category
Registered
Service
vrt
What is port 4991?
Port 4991/TCP is a Registered port, registered with IANA for specific applications. It is associated with the vrt service.
VITA Radio Transport
Useful commands
nmapnmap -p 4991 -sV example.comnetcatnc -zv example.com 4991curlcurl -v http://example.com:4991/telnettelnet example.com 4991bash(echo > /dev/tcp/example.com/4991) 2>/dev/nullFirewall commands
UFWAllow
sudo ufw allow 4991/tcpDeny
sudo ufw deny 4991/tcpiptablesAllow
sudo iptables -A INPUT -p tcp --dport 4991 -j ACCEPTDeny
sudo iptables -D INPUT -p tcp --dport 4991 -j ACCEPTfirewalldAllow
sudo firewall-cmd --permanent --add-port=4991/tcpWindowsAllow
netsh advfirewall firewall add rule name="Open Port 4991" dir=in action=allow protocol=TCP localport=4991Security 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- Outdated versions with vulnerabilities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 4991/TCP?
Port 4991/TCP is associated with the vrt service. VITA Radio Transport
Is it safe to expose port 4991 to the Internet?
It depends on the service and configuration. Port 4991 (vrt) 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 4991 is open?
You can use nmap: `nmap -p 4991 -sV example.com`, netcat: `nc -zv example.com 4991`, or the bash command: `(echo > /dev/tcp/example.com/4991) 2>/dev/null && echo "Open" || echo "Closed"`.
How do I open or close port 4991 on my firewall?
On Linux with UFW: `sudo ufw allow 4991/tcp` (open) or `sudo ufw deny 4991/tcp` (close). With iptables: `sudo iptables -A INPUT -p tcp --dport 4991 -j ACCEPT`. On Windows: `netsh advfirewall firewall add rule name="Open Port 4991" dir=in action=allow protocol=TCP localport=4991`.
What applications and services use port 4991?
Port 4991/TCP is used by the vrt service. Specific uses depend on the software and configuration. Check our related tools section for more information.