Apache 2.4 ErrorDocument for multiple subdomains

Question

we're running a large project for different customers, each has its own subdomain. Apache should not execute any script if an invalid subdomain is used. Instead, an error page should be shown.

Working:

this is out zzz-default.conf which is the last VHOST and matches all queries that are not catched by another VHOST.

<VirtualHost *:80> ServerName project.example.com ServerAlias *.project.example.com Redirect 404 / DocumentRoot /var/www/html/ ErrorDocument 404 "This Subdomain does not exist." ErrorLog ${APACHE_LOG_DIR}/error.log CustomLog ${APACHE_LOG_DIR}/access.log combined </VirtualHost> 

What's not working:

ErrorDocument 404 /404.html 

This file is located in /var/www/html/ and contains pure html, no scripts.

Our problem seems to be the redirect rule, but we need this to match all subdomains and rewrite to /.

If I enable this and call an invalid subdomain, I get

Not Found

The requested URL / was not found on this server.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

Anybody knows why?

Edit: The other VHOSTs are defined as

<VirtualHost *:80> ServerName client.project.example.com Header always append X-Frame-Options SAMEORIGIN </VirtualHost> Include /path/to/local/client/httpd-vufind.conf 

There are 13 VHOSTs defined like this and then the above zzz-default.conf is loaded.

Answer 1

The problem is the redirect rule that matches everything, including your ErrorDocument. The solution is quite simple include the redirect in the 404 response by setting remote URL as the ErrorDocument:

<VirtualHost *:80> ServerName project.example.com ServerAlias *.project.example.com DocumentRoot /var/www/html/ ErrorDocument 404 http://project.example.com/404.html </VirtualHost> 

Answer 2

Solution:

<VirtualHost *:80> ServerName project.example.com ServerAlias *.project.example.com # CHANGED: # return 404 for all requests expect 404.html RedirectMatch 404 "^(/(?!404.html).*)" # use custom 404 error document ErrorDocument 404 /404.html DocumentRoot /var/www/html/ ErrorLog ${APACHE_LOG_DIR}/error.log CustomLog ${APACHE_LOG_DIR}/access.log combined </VirtualHost> 

The problem is, that the "Redirect 404 /" prevents that the 404.html itself (configured with the ErrorDocument statement) can be shown. This is indicated by the error message: "Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request."