All ports
Port3849/UDP
spw-dnspreloadPort
3849
Protocol
UDP
Category
Registered
Service
spw-dnspreload
What is port 3849?
Port 3849/UDP is a Registered port, registered with IANA for specific applications. It is associated with the spw-dnspreload service.
SPACEWAY DNS Preload
Useful commands
nmapnmap -p 3849 -sV example.comnetcatnc -zv example.com 3849curlcurl -v http://example.com:3849/telnettelnet example.com 3849bash(echo > /dev/udp/example.com/3849) 2>/dev/nullFirewall commands
UFWAllow
sudo ufw allow 3849/udpDeny
sudo ufw deny 3849/udpiptablesAllow
sudo iptables -A INPUT -p udp --dport 3849 -j ACCEPTDeny
sudo iptables -D INPUT -p udp --dport 3849 -j ACCEPTfirewalldAllow
sudo firewall-cmd --permanent --add-port=3849/udpWindowsAllow
netsh advfirewall firewall add rule name="Open Port 3849" dir=in action=allow protocol=UDP localport=3849Security 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 3849/UDP?
Port 3849/UDP is associated with the spw-dnspreload service. SPACEWAY DNS Preload
Is it safe to expose port 3849 to the Internet?
It depends on the service and configuration. Port 3849 (spw-dnspreload) 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 3849 is open?
You can use nmap: `nmap -p 3849 -sV example.com`, netcat: `nc -zv example.com 3849`, or the bash command: `(echo > /dev/udp/example.com/3849) 2>/dev/null && echo "Open" || echo "Closed"`.
How do I open or close port 3849 on my firewall?
On Linux with UFW: `sudo ufw allow 3849/udp` (open) or `sudo ufw deny 3849/udp` (close). With iptables: `sudo iptables -A INPUT -p udp --dport 3849 -j ACCEPT`. On Windows: `netsh advfirewall firewall add rule name="Open Port 3849" dir=in action=allow protocol=UDP localport=3849`.
What applications and services use port 3849?
Port 3849/UDP is used by the spw-dnspreload service. Specific uses depend on the software and configuration. Check our related tools section for more information.