When migrating domains in Apache, many developers encounter a common pitfall with RewriteCond directives. The default behavior chains conditions with AND logic, but we often need OR conditions for domain redirection scenarios.

# This doesn't work as expected (AND logic)
RewriteCond %{HTTP_HOST} ^olddomain.com [NC]
RewriteCond %{HTTP_HOST} ^www.olddomain.com [NC]
RewriteCond %{HTTP_HOST} ^newdomain.com [NC]
RewriteRule ^/(.*)$ http://www.newdomain.com/$1 [R=301,NC]

The simplest approach is to use the [OR] flag on conditions:

RewriteEngine on
RewriteCond %{HTTP_HOST} ^olddomain\.com$ [NC,OR]
RewriteCond %{HTTP_HOST} ^www\.olddomain\.com$ [NC,OR]
RewriteCond %{HTTP_HOST} ^newdomain\.com$ [NC]
RewriteRule ^(.*)$ http://www.newdomain.com/$1 [R=301,L]

For cleaner configuration with fewer conditions:

RewriteEngine on
RewriteCond %{HTTP_HOST} ^(www\.)?(olddomain|newdomain)\.com$ [NC]
RewriteRule ^(.*)$ http://www.newdomain.com/$1 [R=301,L]

• Always use R=301 for permanent SEO-friendly redirects
• The L flag stops further rule processing
• Escape dots in domain names (\.)
• Consider adding QSA flag if you need to preserve query strings

    ServerAdmin webmaster@localhost
    ServerName newdomain.com
    ServerAlias www.newdomain.com olddomain.com www.olddomain.com
    
    RewriteEngine on
    RewriteCond %{HTTP_HOST} !^www\.newdomain\.com$ [NC]
    RewriteRule ^(.*)$ http://www.newdomain.com/$1 [R=301,L]
    
    DocumentRoot /var/www/newdomain.com/www/
    # Other configurations...

Use curl -I to verify redirects:

curl -I http://olddomain.com
curl -I http://www.olddomain.com/some-page
curl -I http://newdomain.com/about

When migrating from olddomain.com to newdomain.com, proper URL handling becomes crucial for SEO preservation. The key requirement is to redirect all variations (with/without www, old/new domains) to a single canonical URL (www.newdomain.com).

The original approach attempts to handle multiple domains using consecutive RewriteCond directives:

RewriteCond %{HTTP_HOST} ^olddomain.com [NC]
RewriteCond %{HTTP_HOST} ^www.olddomain.com [NC]
RewriteCond %{HTTP_HOST} ^newdomain.com [NC]
RewriteRule ^/(.*)$ http://www.newdomain.com/$1 [R=301,NC]

This creates an AND relationship between conditions - meaning ALL conditions must match simultaneously (which is impossible). What we actually need is an OR relationship.

Option 1: Using the [OR] Flag

The simplest solution is adding the OR flag between conditions:

RewriteCond %{HTTP_HOST} ^olddomain\.com$ [NC,OR]
RewriteCond %{HTTP_HOST} ^www\.olddomain\.com$ [NC,OR]
RewriteCond %{HTTP_HOST} ^newdomain\.com$ [NC]
RewriteRule ^(.*)$ http://www.newdomain.com/$1 [R=301,L]

Option 2: Regular Expression Pattern Matching

Combine patterns into a single condition using regex alternation:

RewriteCond %{HTTP_HOST} ^(www\.)?(old|new)domain\.com$ [NC]
RewriteRule ^(.*)$ http://www.newdomain.com/$1 [R=301,L]

Option 3: Separate Rules for Each Case

Some prefer explicit rules for better readability:

RewriteCond %{HTTP_HOST} ^olddomain\.com$ [NC]
RewriteRule ^(.*)$ http://www.newdomain.com/$1 [R=301,L]

RewriteCond %{HTTP_HOST} ^www\.olddomain\.com$ [NC]
RewriteRule ^(.*)$ http://www.newdomain.com/$1 [R=301,L]

RewriteCond %{HTTP_HOST} ^newdomain\.com$ [NC]
RewriteRule ^(.*)$ http://www.newdomain.com/$1 [R=301,L]

• Always use 301 (permanent) redirects for SEO
• Test with curl -I before going live
• The [L] flag terminates further processing
• Escape dots in domain names (\. instead of .)
• Consider adding these rules to .htaccess if you don't have server access

Here's the full corrected configuration:

<VirtualHost *:80>
    ServerAdmin webmaster@localhost
    ServerName newdomain.com
    ServerAlias www.newdomain.com olddomain.com www.olddomain.com
    DocumentRoot /var/www/newdomain.com/www/

    RewriteEngine on
    RewriteCond %{HTTP_HOST} !^www\.newdomain\.com$ [NC]
    RewriteCond %{HTTP_HOST} ^(www\.)?(old|new)domain\.com$ [NC]
    RewriteRule ^(.*)$ http://www.newdomain.com/$1 [R=301,L]

    # Other configuration...
</VirtualHost>