Can TCP and UDP Share the Same Port? A Deep Dive into Port Mechanics

This article breaks down the interview question "Can TCP and UDP use the same port?" by examining protocol-level port spaces, client‑side TCP and UDP port sharing rules, server‑side TCP reuse with SO_REUSEADDR, and UDP reuse with SO_REUSEPORT, complete with code examples and practical implications.

Network programmingPort SharingSO_REUSEADDR

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Can TCP and UDP Share the Same Port? A Deep Dive into Port Mechanics

Liangxu Linux

Aug 2, 2022 · Backend Development

Can TCP and UDP Bind to the Same Port Simultaneously? A Deep Dive into Port Management

This article explains why TCP and UDP can share the same port number, how multiple TCP processes handle binding, client port reuse, TIME_WAIT implications, and practical solutions like SO_REUSEADDR and tcp_tw_reuse to avoid address‑in‑use errors.

Linux networkingPort BindingSO_REUSEADDR

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Can TCP and UDP Bind to the Same Port Simultaneously? A Deep Dive into Port Management

Liangxu Linux

Jan 17, 2021 · Fundamentals

When Do SO_REUSEADDR and SO_REUSEPORT Actually Take Effect? A Deep Dive

This article explains the differences and interactions between the SO_REUSEADDR and SO_REUSEPORT socket options, shows how they behave on BSD and Linux kernels across versions, and provides code examples and tables to illustrate binding rules, TIME_WAIT handling, and the evolution of reuse‑port support.

Linux kernelSO_REUSEADDRSO_REUSEPORT

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When Do SO_REUSEADDR and SO_REUSEPORT Actually Take Effect? A Deep Dive