← Back to all network ports
TCP/UDP
Unknown
53 DNS
DNS resolves hostnames, serves zone transfers, and supports service discovery across most networks.
Security Context
Port 53 is context-dependent. Its risk depends on the daemon behind it, whether the traffic is encrypted, and how tightly the listener is scoped to trusted networks.
- !Open resolvers can be abused in reflection and amplification attacks.
Nmap Check
Use a version probe first so you confirm whether the expected service is really what is listening on this port.
nmap -sS -sU -p 53 <host>Firewall Commands
UFW
sudo ufw allow 53/tcp
sudo ufw allow 53/udpiptables
sudo iptables -A INPUT -p tcp --dport 53 -j ACCEPT
sudo iptables -A INPUT -p udp --dport 53 -j ACCEPT