Port 53 — DNS
Port 53 (TCP/UDP) is used by DNS. Domain Name System — resolves names to IP addresses. UDP for queries, TCP for zone transfers and large responses.
Port 53 at a glance
| Property | Value |
|---|---|
| Port number | 53 |
| Transport | TCP/UDP |
| Service | DNS |
| Category | Well-known port |
What it is used for
Domain Name System — resolves names to IP addresses. UDP for queries, TCP for zone transfers and large responses.
Security considerations
Target for spoofing and amplification attacks. Use DNSSEC and restrict recursion.
See our full TCP/UDP port reference and learn how firewalls filter ports in the CyberOps course.
Frequently asked questions
What is port 53 used for?
Port 53 (TCP/UDP) is used by DNS. Domain Name System — resolves names to IP addresses. UDP for queries, TCP for zone transfers and large responses.
Is port 53 TCP or UDP?
Port 53 uses TCP/UDP.
Is it safe to open port 53?
Target for spoofing and amplification attacks. Use DNSSEC and restrict recursion.
Related
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