What protocol does DNS use?
Understand the Problem
The question is asking about the specific protocol used by DNS (Domain Name System) to perform its functions, such as translating domain names into IP addresses.
Answer
UDP and TCP port 53
DNS primarily uses UDP for queries on port 53 but can fall back to TCP when the packet size exceeds the limit of a single UDP packet.
Answer for screen readers
DNS primarily uses UDP for queries on port 53 but can fall back to TCP when the packet size exceeds the limit of a single UDP packet.
More Information
DNS was designed to use both UDP and TCP since its inception. Typically, UDP is preferred due to its low latency and low overhead, making it suitable for handling numerous repeated requests quickly. TCP is required when packet sizes are too large to be handled by UDP.
Tips
A common mistake is to assume DNS only uses one protocol exclusively, whereas it uses both depending on the size of the data packets.
Sources
- is-dns-tcp-or-udp-port-53 - infoblox.com
- Why does DNS use UDP and not TCP? - geeksforgeeks.org
- DNS works on both TCP and UDP - Windows Server - learn.microsoft.com
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