This article uses a playful story of a Linux process to explain the real limits on TCP connections, covering the configurable port range, file descriptor caps, thread model constraints, memory usage, and CPU saturation, and shows how to adjust these limits on a Linux server.
When a Kubernetes pod that previously created connections stops working and reports “Address not available”, the root cause is often exhaustion of the kernel’s random port range, which can be resolved by adjusting net.ipv4.ip_local_port_range and aligning it with ServiceNodePortRange settings.
This article explains how Linux manages TCP sockets at the kernel level, demonstrates how to adjust port ranges and file‑descriptor limits, and shows the key data structures and lookup functions that enable high‑concurrency TCP connections, providing practical guidance for scaling client connections.
This article explains how to adjust Linux kernel port ranges and file descriptor limits, explores the internal structures of TCP sockets, and walks through key kernel functions such as tcp_v4_rcv and __inet_lookup that locate sockets based on IP and port tuples, providing practical guidance for increasing TCP concurrency.
