Port Selection — 2 Technical Articles

Sep 4, 2021 · Fundamentals

How Does Linux Choose a Client Port for TCP Connections? Deep Dive into the Kernel

This article explains the Linux kernel's process for selecting a client-side TCP port during connect() and bind(), covering the relevant source code, random port selection algorithm, conflict checks, and common error scenarios such as "Cannot assign requested address".

KernelLinuxNetworking

0 likes · 17 min read

How Does Linux Choose a Client Port for TCP Connections? Deep Dive into the Kernel

Refining Core Development Skills

Jun 17, 2021 · Fundamentals

How Linux Determines the Client Port for TCP Connections

On Linux, the client port used in a TCP connection is selected either by the kernel during the connect system call—randomly scanning the ip_local_port_range while respecting reserved ports—or by a prior bind call, with detailed kernel functions such as inet_hash_connect and __inet_hash_connect governing the process.

KernelLinuxNetworking

0 likes · 21 min read

How Linux Determines the Client Port for TCP Connections