TCP vs UDP: How They Work and When to Use Each

A practical comparison of reliability, latency, and overhead in the internet's two core transport protocols.

Compare the transports

Start with the application's requirements: must every message arrive, and must order be preserved? TCP establishes a connection and retransmits lost segments; UDP sends datagrams without those guarantees. DNS commonly uses UDP first, but large responses and some scenarios require TCP.

dig example.com A
dig +tcp example.com A

Compare answers and timing. A difference alone is not a failure: routing, cache state, and resolver policy may vary.

Check it with Net Utils

Use the relevant Net Utils tool and compare the structured output with your expected configuration. Public network data changes, so confirm important conclusions with a repeat test.