Nginx HTTP跳转异常：访问HTTP域名跳转到localhost而非指定域名

Hey there, let's break down why your redirect is misbehaving and how to fix it quickly.

What's Causing the Problem? #

From your config, I spot two likely culprits:

1. Conflicting default_server settings: Your HTTP server block uses listen 80 default;, but if there's another config file in /etc/nginx/conf.d/ (like the default default.conf) that also claims default_server on port 80, Nginx might be routing your requests to that unconfigured block instead of your custom redirect rule. That would explain why it's falling back to localhost.
2. $server_name isn't always reliable: The $server_name variable pulls directly from your Nginx config's server_name value, but if for some reason the request's Host header doesn't match exactly (or Nginx picks the wrong server block), it won't return the domain you expect. The $host variable is better here because it grabs the Host header directly from the incoming request.

Step-by-Step Fixes #

1. Resolve default_server Conflicts & Use $host

First, check if there's a conflicting default config:

• Navigate to /etc/nginx/conf.d/ and look for files like default.conf. If you find one with listen 80 default_server;, either delete the file or edit it to remove the default_server flag (so it doesn't compete with your custom block).

Then update your HTTP redirect server block to use $host instead of $server_name, and make sure it listens on both IPv4 and IPv6:

server {
    listen 80;
    listen [::]:80;
    server_name www.example.com;
    return 301 https://$host$request_uri;
}

2. (Alternative) Mark Your Block as the Definitive Default Server

If you want to keep other config files around, explicitly set your redirect block as the default_server for port 80 (only one default_server can exist per port):

server {
    listen 80 default_server;
    listen [::]:80 default_server;
    server_name www.example.com;
    return 301 https://$host$request_uri;
}

Verify & Apply Changes #

Before restarting Nginx, always check your config for syntax errors:

nginx -t

If you see "test is successful", restart Nginx to apply the fix:

systemctl restart nginx

This should make sure all HTTP requests to www.example.com get redirected to the correct HTTPS URL instead of localhost.

内容的提问来源于stack exchange，提问作者VictorGalisson