Apache HTTPD Configuration

Instructions

Configure Apache HTTP Server for production hosting and reverse proxy use cases.

VirtualHost setup:

• Define :80> and :443> blocks per site with ServerName and ServerAlias
• Use DocumentRoot to set the web root for each virtual host
• Separate site configs into /etc/apache2/sites-available/ and enable with a2ensite

URL rewriting with mod_rewrite:

• Enable with a2enmod rewrite and set AllowOverride All in the directory block
• Use RewriteEngine On, RewriteCond, and RewriteRule for URL transformations
• Common patterns: trailing slash enforcement, www/non-www canonicalization, HTTP-to-HTTPS redirect
• Prefer RewriteRule in VirtualHost config over .htaccess for performance

Reverse proxying with mod_proxy:

• Enable mod_proxy and mod_proxy_http with a2enmod proxy proxy_http
• Use ProxyPass /api/ http://localhost:8000/api/ and matching ProxyPassReverse directives
• Set ProxyPreserveHost On to forward the original Host header
• Add RequestHeader set X-Forwarded-Proto "https" when terminating SSL at Apache

.htaccess for directory-level overrides:

• Use sparingly — each request triggers a filesystem walk to find .htaccess files
• Common uses: auth (AuthType Basic), rewrite rules, custom error pages, MIME types
• Disable with AllowOverride None in production when rules can live in VirtualHost config

SSL/TLS with mod_ssl:

• Enable with a2enmod ssl and configure SSLCertificateFile, SSLCertificateKeyFile, SSLCertificateChainFile
• Set SSLProtocol all -SSLv3 -TLSv1 -TLSv1.1 and strong SSLCipherSuite
• Use certbot --apache plugin for automated Let’s Encrypt integration

Performance tuning:

• Choose the right MPM: event (recommended for modern workloads), worker (threaded), prefork (process-based, required for mod_php)
• Enable KeepAlive On with reasonable MaxKeepAliveRequests (100) and KeepAliveTimeout (5)
• Enable mod_deflate for compression and mod_expires for cache headers

Migration path to Nginx:

• Map VirtualHost blocks to Nginx server blocks
• Replace mod_rewrite rules with Nginx rewrite and location directives
• Replace ProxyPass with Nginx proxy_pass in location blocks
• Eliminate .htaccess — Nginx has no equivalent; all config is centralized