Wildcard DNS / sub domains - Wildcard Hosting

If you have privilege to edit the DNS zone, you will have to add the following entries.
Example:
*.domain-name.com. IN A 121.0.0.1

Once the DNS propagation gets completed. You can try digging any sub domains.
Example:
test.domain-name.com
abc.domain-name.com
123.domain-name.com

All the above sub domain will point to the server.

Now all the sub domains are pointing to the server. But there is no virtual
host entry for it. So you will get the Apache page.
You just need to edit the virtual host entries for that particular domain. Add a ServerAlias " *.domain-name.com ".

Example:
<VirtualHost IP:443>
ServerName domain-name.com
ServerAlias *.domain-name.com
DocumentRoot /home/user/public_html/
....................
.............
</VirtualHost>

The restart Apache.
Now accessing any sub domains will give up the main website page.
This is not what you are looking for. You want the sub domains to point to its respective folder.

Example:
Accessing " test.domain-name.com ", should point to the test folder under " public_html " directory.
To get this done, we can use Rewrite conditions.

To make each sub domain redirect to its correct folder, you can use the
rewrite rules.
Open the .htaccess file under " public_html " and add the below given entries.

Example:
RewriteEngine On
RewriteCond %{HTTP_HOST} !^www\.domain\.com
RewriteCond %{HTTP_HOST} ([^.]+)\.domain\.com [NC]
RewriteRule ^(.*)$ https://www.domain.com/%1 [L,R]