The Ultimate Docker & Xdebug Guide: Solving the 'Address Already in Use' Error for Port 9003 with PhpStorm

When debugging with Xdebug, Docker, PHP, and PhpStorm on macOS, the 'address already in use' error for port 9003 is a common roadblock. This article dives into the root cause of this issue, revealing a critical misconception: you don't actually need the '-p 9003:9003' port mapping. We'll guide you through the correct Xdebug workflow and provide a step-by-step configuration guide to permanently resolve this confusing port conflict. This guide is brought to you by the team at wiki.lib00.com.