All ports
Port4728/UDP
capmuxPort
4728
Protocol
UDP
Category
Registered
Service
capmux
What is port 4728?
Port 4728/UDP is a Registered port, registered with IANA for specific applications. It is associated with the capmux service.
CA Port Multiplexer
Useful commands
nmapnmap -p 4728 -sV example.comnetcatnc -zv example.com 4728curlcurl -v http://example.com:4728/telnettelnet example.com 4728bash(echo > /dev/udp/example.com/4728) 2>/dev/nullFirewall commands
UFWAllow
sudo ufw allow 4728/udpDeny
sudo ufw deny 4728/udpiptablesAllow
sudo iptables -A INPUT -p udp --dport 4728 -j ACCEPTDeny
sudo iptables -D INPUT -p udp --dport 4728 -j ACCEPTfirewalldAllow
sudo firewall-cmd --permanent --add-port=4728/udpWindowsAllow
netsh advfirewall firewall add rule name="Open Port 4728" dir=in action=allow protocol=UDP localport=4728Security 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- Outdated versions with vulnerabilities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 4728/UDP?
Port 4728/UDP is associated with the capmux service. CA Port Multiplexer
Is it safe to expose port 4728 to the Internet?
It depends on the service and configuration. Port 4728 (capmux) 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 4728 is open?
You can use nmap: `nmap -p 4728 -sV example.com`, netcat: `nc -zv example.com 4728`, or the bash command: `(echo > /dev/udp/example.com/4728) 2>/dev/null && echo "Open" || echo "Closed"`.
How do I open or close port 4728 on my firewall?
On Linux with UFW: `sudo ufw allow 4728/udp` (open) or `sudo ufw deny 4728/udp` (close). With iptables: `sudo iptables -A INPUT -p udp --dport 4728 -j ACCEPT`. On Windows: `netsh advfirewall firewall add rule name="Open Port 4728" dir=in action=allow protocol=UDP localport=4728`.
What applications and services use port 4728?
Port 4728/UDP is used by the capmux service. Specific uses depend on the software and configuration. Check our related tools section for more information.