When starting Apache2, you might encounter this common but harmless warning:

apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.1.1 for ServerName

This occurs when Apache cannot find a global ServerName directive. While the server will still function, it's best practice to properly configure this setting.

There are two approaches to resolve this:

Option 1: Set ServerName in httpd.conf or apache2.conf

# Edit the main configuration file
sudo nano /etc/apache2/apache2.conf

# Add this line (replace with your actual domain or IP)
ServerName localhost

Option 2: Update hosts file properly

Your current /etc/hosts has some issues:

# Problematic configuration (commented lines create confusion)
#127.0.0.1  hpdtp-ubuntu910
#testproject.localhost  localhost.localdomain   localhost
#127.0.1.1  hpdtp-ubuntu910

# Recommended configuration
127.0.0.1   localhost testproject.localhost
127.0.1.1   hpdtp-ubuntu910

Your 000-default configuration looks mostly correct, but let's enhance it:

    ServerAdmin webmaster@testproject.localhost
    ServerName testproject.localhost
    ServerAlias www.testproject.localhost
    DocumentRoot "/home/morpheous/work/websites/testproject/web"
    
    
        Options Indexes FollowSymLinks
        AllowOverride All
        Require all granted
    

    ErrorLog ${APACHE_LOG_DIR}/testproject_error.log
    CustomLog ${APACHE_LOG_DIR}/testproject_access.log combined
    
    Alias /sf /lib/vendor/symfony/symfony-1.3.2/data/web/sf
    
        AllowOverride All
        Require all granted
    

If you're getting a blank page at http://testproject.localhost:

1. Check directory permissions: ls -la /home/morpheous/work/websites/testproject/web
2. Verify PHP is working: create test.php with
3. Check error logs: tail -f /var/log/apache2/error.log

After making changes:

sudo apache2ctl configtest
sudo systemctl restart apache2

The warning should disappear, and your site should load properly. If issues persist, check SELinux/apparmor settings and firewall configurations.

---

When working with Apache2 on Linux systems, you might encounter this warning during server restart:

apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.1.1 for ServerName

While this warning doesn't prevent Apache from functioning, it indicates a configuration gap that could lead to unexpected behavior, especially when combined with virtual host setups.

The warning appears when Apache cannot find a proper ServerName directive. Let's examine your current setup:

# Current /etc/hosts content
127.0.0.1   localhost
127.0.0.1   testproject.localhost
127.0.1.1   hpdtp-ubuntu910

And your virtual host configuration:

<VirtualHost *:80>
  ServerName testproject.localhost
  DocumentRoot "/home/morpheous/work/websites/testproject/web"
  DirectoryIndex index.php
  <Directory "/home/morpheous/work/websites/testproject/web">
    AllowOverride All
    Allow from All
  </Directory>

  Alias /sf /lib/vendor/symfony/symfony-1.3.2/data/web/sf
  <Directory "/lib/vendor/symfony/symfony-1.3.2/data/web/sf">
    AllowOverride All
    Allow from All
  </Directory>
</VirtualHost>

1. Fix the FQDN Warning:

Add a global ServerName directive to your Apache configuration:

# Edit /etc/apache2/apache2.conf
ServerName localhost

Or alternatively, create a dedicated config file:

# Create /etc/apache2/conf-available/fqdn.conf
echo "ServerName localhost" | sudo tee /etc/apache2/conf-available/fqdn.conf
sudo a2enconf fqdn
sudo service apache2 restart

2. Verify Hosts File Configuration:

Optimize your /etc/hosts file:

127.0.0.1   localhost testproject.localhost
127.0.1.1   hpdtp-ubuntu910

# IPv6 configuration remains unchanged
::1     localhost ip6-localhost ip6-loopback

3. Debug the Blank Page Issue:

Check several key areas when facing blank pages:

# Check Apache error logs
tail -f /var/log/apache2/error.log

# Verify directory permissions
ls -la /home/morpheous/work/websites/testproject/web

# Check if PHP is processing
echo "<?php phpinfo(); ?>" > /home/morpheous/work/websites/testproject/web/info.php

For more robust virtual hosting, consider this enhanced configuration:

<VirtualHost *:80>
    ServerName testproject.localhost
    ServerAlias www.testproject.localhost
    ServerAdmin webmaster@localhost
    
    DocumentRoot "/home/morpheous/work/websites/testproject/web"
    DirectoryIndex index.php index.html
    
    ErrorLog ${APACHE_LOG_DIR}/testproject-error.log
    CustomLog ${APACHE_LOG_DIR}/testproject-access.log combined

    <Directory "/home/morpheous/work/websites/testproject/web">
        Options Indexes FollowSymLinks MultiViews
        AllowOverride All
        Require all granted
        
        <IfModule mod_php7.c>
            php_admin_value upload_max_filesize "128M"
            php_admin_value post_max_size "128M"
        </IfModule>
    </Directory>

    # Symfony specific configuration
    Alias /sf /lib/vendor/symfony/symfony-1.3.2/data/web/sf
    <Directory "/lib/vendor/symfony/symfony-1.3.2/data/web/sf">
        AllowOverride None
        Require all granted
    </Directory>
</VirtualHost>

• Having conflicting ServerName directives in multiple files
• Incorrect file permissions on web directories
• Missing PHP module or incorrect PHP handler configuration
• DNS caching issues (flush with sudo systemd-resolve --flush-caches)

After implementing these changes:

# Test configuration syntax
apache2ctl configtest

# Restart Apache
sudo systemctl restart apache2

# Verify HTTP response
curl -I http://testproject.localhost

This comprehensive approach should resolve both the FQDN warning and the blank page issue while providing a more robust hosting environment for your Symfony project.