Basic Nginx Configuration and 403 Error Troubleshooting Guide

Basic Nginx configuration directives are explained, including #user nobody nobody; # configure user or group,

#worker_processes 2;   # number of worker processes (default 1)

, #pid /nginx/pid/nginx.pid; # PID file location, error_log log/error.log debug; # log path and level, event settings such as accept_mutex on; and multi_accept on;, and HTTP block settings like include mime.types;, default_type application/octet-stream;, custom log_format, access_log, sendfile on;, keepalive_timeout 65;. It also covers upstream definition, server block parameters, and location matching with regular expressions.

The article then presents a real‑world 403 error case encountered on an Alibaba Cloud server, showing screenshots of the error page and the relevant configuration sections.

Four troubleshooting steps are outlined: (1) ensure the Nginx start‑up user matches the user defined in the configuration; (2) verify that an index file (index.html or index.php) exists in the document root; (3) check file system permissions for the web directory; (4) confirm that access restrictions (allow/deny directives or firewall rules) are not unintentionally blocking external requests.

Command examples such as ps -ef | grep nginx | awk '{print $1}' to view the running user are provided, and the article advises updating the user directive in nginx.conf to match the actual start‑up user.

Additional references link to iptables command guides, Nginx compilation tutorials, and Ansible configuration examples for batch server deployment.