Ticket #27927: 27927.diff

src/wp-includes/ms-settings.php

@@ -35 +35 @@
                 $_SERVER['HTTP_HOST'] = substr( $_SERVER['HTTP_HOST'], 0, -4 );
         }
 
+        // www is an illegal subdomain in multisite. If it exists in the requested URL,
+        // we strip it so that template_redirect initiates the proper 301
+        if ( is_subdomain_install() && substr( $domain, 0, 4 ) == 'www.' ) {
+                $domain = substr( $domain, 4 );
+        }
+
         $path = strtolower( stripslashes( $_SERVER['REQUEST_URI'] ) );
         if ( is_admin() ) {
                 $path = preg_replace( '#(.*)/wp-admin/.*#', '$1/', $path );