All ports
Port5353/UDP
mdnsPort
5353
Protocol
UDP
Category
Registered
Service
mdns
What is port 5353?
Port 5353/UDP is a Registered port, registered with IANA for specific applications. It is associated with the mdns service.
Multicast DNS
Useful commands
nmapnmap -p 5353 -sV example.comnetcatnc -zv example.com 5353curlcurl -v http://example.com:5353/telnettelnet example.com 5353bash(echo > /dev/udp/example.com/5353) 2>/dev/nullFirewall commands
UFWAllow
sudo ufw allow 5353/udpDeny
sudo ufw deny 5353/udpiptablesAllow
sudo iptables -A INPUT -p udp --dport 5353 -j ACCEPTDeny
sudo iptables -D INPUT -p udp --dport 5353 -j ACCEPTfirewalldAllow
sudo firewall-cmd --permanent --add-port=5353/udpWindowsAllow
netsh advfirewall firewall add rule name="Open Port 5353" dir=in action=allow protocol=UDP localport=5353Security Risks
- DNS cache poisoning attacks
- DDoS amplification using open DNS resolvers
- Information disclosure of internal subdomains
- Domain hijacking if DNS server is misconfigured
Frequently Asked Questions
What service runs on port 5353/UDP?
Port 5353/UDP is associated with the mdns service. Multicast DNS
Is it safe to expose port 5353 to the Internet?
It depends on the service and configuration. Port 5353 (mdns) 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 5353 is open?
You can use nmap: `nmap -p 5353 -sV example.com`, netcat: `nc -zv example.com 5353`, or the bash command: `(echo > /dev/udp/example.com/5353) 2>/dev/null && echo "Open" || echo "Closed"`.
How do I open or close port 5353 on my firewall?
On Linux with UFW: `sudo ufw allow 5353/udp` (open) or `sudo ufw deny 5353/udp` (close). With iptables: `sudo iptables -A INPUT -p udp --dport 5353 -j ACCEPT`. On Windows: `netsh advfirewall firewall add rule name="Open Port 5353" dir=in action=allow protocol=UDP localport=5353`.
What applications and services use port 5353?
Port 5353/UDP is used by the mdns service. Specific uses depend on the software and configuration. Check our related tools section for more information.