Web server configuration

Troubleshooting web server issues involves checking various elements, from configuration settings to log files. Common problems are not always evident as errors in error_log, so a comprehensive approach is needed.

Webserver logs

The first step in troubleshooting is to examine the log files. Each virtual server or sub-server in Virtualmin has its own log files located in /home/example/logs (replace example with your server name). The error_log is typically the most informative, but access_log may also provide useful insights.

The wrong site shows up

If visiting a domain on your server shows incorrect content, it could be due to an IP address mismatch:

  1. Check Server IP Addresses:

    • Use ip addr to list the IP addresses on your server.

  2. Review Apache configuration:

    • Check the VirtualHost settings in Apache configuration:
      grep -i 'virtualhost' /etc/apache2/sites-enabled/*.conf 2>/dev/null || grep -i 'virtualhost' /etc/httpd/conf/httpd.conf 2>/dev/null
    • Ensure that the IP addresses listed match those from ip addr.
    • Verify that each VirtualHost block lists an IP address, not an asterisk (i.e. *).

  3. Restart Apache:

    • For RHEL derivatives: systemctl restart httpd.
    • For Debian derivatives: systemctl restart apache2.

Virtualmin configuration settings

Review Virtualmin settings to ensure new records are correctly created:

  1. Network settings

    • System Settings ⇾ Virtualmin Configuration ⇾ Network settings: Can be opened from the navigation menu.
    • Network interface for virtual addresses: Should typically be the primary IP address of your server (commonly enp0s5 or eth0).
    • Default virtual server IPv4/IPv6 address: Recommended to leave as From Network Interface.
    • Default IP address for DNS records: Set to Automatically detect external address if behind a NAT router.

  2. Defaults for new domains

    • System Settings ⇾ Virtualmin Configuration ⇾ Defaults for new domains: Can be opened from the navigation menu.
    • Address format for Apache virtual hosts: Use Always use * for dynamic IPs, otherwise Always use IP. Default is set to Decide automatically.

Internal server error

Specifically, 500 Internal Server Errors is common error often does not provide clear messages in error_log. Key areas to check:

  1. Permissions: Scripts with permissions set too loosely (e.g., 777) won’t execute in a suEXEC environment. Correct permissions are 750 or less.
  2. Script bugs: Check for syntax errors or compatibility issues with PHP.
    • Test syntax: php -l scriptname.php.
  3. File ownership: Ensure files are owned by the domain owner. Incorrect ownership can lead to access issues for the suEXEC process.
    • Correct ownership: chown -R domainname:domainname scriptdirectory.

Previewing websites before DNS updates

Previewing within Virtualmin

Virtualmin provides a convenient way to preview a site before DNS records are fully propagated. To do this:

  1. Log into Virtualmin.
  2. Navigate to Web Configuration ⇾ Preview Website.
  3. Virtualmin will retrieve and display the website within the control panel, allowing you to navigate and interact with it.

Using an alias for preview

A recommended approach is to set up an alias so that users can access their site through a URL like https://username.example.com. To configure this:

  1. Go to System Settings ⇾ Server Templates ⇾ Default Template ⇾ Virtual Server Creation.
  2. In the Automatically create alias domain field, add your primary domain.
  3. This setting ensures that every new virtual server created will have an alias domain that customers can use before DNS points to your server.

Discouraging UserDir feature

Virtualmin strongly discourages the use of the Apache UserDir feature (i.e. https://www.example.com/~username) due to potential security issues, particularly in shared hosting environments. For those who still wish to explore this option, refer to the relative Apache documentation.