7. Apache and Nginx: Install and Understand

7.5 Reading an Nginx Server Block

By Ravindra Bagale · Last updated: 27 September 2026

Also in the AWS course: this lesson is the same as 8.2 Reading an Nginx configuration in the AWS course, which is the main version of this page.

Config file vachta aali ki web server tumchya haatat yeto. Nginx madhe directives (naav value;) aani blocks (naav { ... }) astat.

main context  (user, worker_processes, error_log)
 ├── events { worker_connections ... }
 └── http {  (mime types, logging, gzip, include conf.d/*.conf)
        └── server {            ← one per website (a "server block")
               listen ...; server_name ...; root ...;
               └── location /path { ... }   ← rules for part of the URL
            }
     }

A fully commented server block:

# /etc/nginx/conf.d/mysite.conf   (Ubuntu: /etc/nginx/sites-available/mysite)
server {
    listen 80;                          # IPv4 port
    listen [::]:80;                     # IPv6 port
    server_name example.com www.example.com;   # which Host names this block answers

    root  /var/www/mysite;              # document root: URL "/" maps here
    index index.html index.htm;         # file served for a folder request

    location / {
        try_files $uri $uri/ =404;      # file? folder? otherwise 404
    }

    location /images/ {
        expires 7d;                     # let browsers cache images for 7 days
    }

    error_page 404 /404.html;           # custom error page (file inside root)
    autoindex off;                      # never list folder contents

    access_log /var/log/nginx/mysite_access.log;
    error_log  /var/log/nginx/mysite_error.log;
}

How Nginx chooses the server block

1. It looks at blocks whose listen matches the port of the request.
2. Among those, it picks the block whose server_name matches the Host header exactly (then wildcard names like *.example.com).
3. If nothing matches, it uses the block marked default_server for that port, or the first block loaded if none is marked.

That rule explains the most common complaint: "I configured my site but I still see the welcome page." Some other block won, because it is the default or because your server_name doesn't match what the browser sent.