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Port 53: DNS (Domain Name System)

DNS resolves domain names into IP addresses. Operates primarily over UDP 53, and TCP 53 for large replies and zone transfers.

Protocol
TCP / UDP
Category
Core Infrastructure
Common Services
BIND 9, Unbound, PowerDNS, CoreDNS

What is Port 53 and How Does It Work?

DNS resolves domain names into IP addresses. Operates primarily over UDP 53, and TCP 53 for large replies and zone transfers.

Security Vulnerabilities & Attack Vectors on Port 53

Misconfigured open DNS resolvers can be weaponized in DNS amplification DDoS attacks. Enable DNSSEC and rate-limiting.

Auditing & Scanning Port 53 with Nmap

Run the following command to check if Port 53 is reachable and determine service fingerprints:

nmap -p 53 -sU -sS --script dns-recursion

Frequently Asked Questions

How do I check if Port 53 is open?
Use cyber-tool.org diagnostic tools or run 'nc -zv 53' in your terminal to verify open socket connections.
Is it safe to leave Port 53 open to the internet?
Exposing Port 53 (DNS (Domain Name System)) publicly introduces potential exposure. Protect it with IP whitelisting, firewalls, and encryption.