1. Go to  http://www.zend.com/en/products/guard/downloads
   (site may require that you sign up – it’s free)
2. Tic the circle in front of Zend Optimizer v3.3
3. Select package Linux x86 (32bit) version
4. Download
5. Unzip/untar  the file on your PC which creates a folder named ZendOptimizer-3.3.3-linux-glibc23-i386
6. Open ZendOptimizer-3.3.3-linux-glibc23-i386
7. Open Data folder
8. Open 5_2_x_comp folder
   (the 5.2.x matches your PHP version)

   You should see this file: ZendOptimizer.so 1,381 KB
   (1.34 MB (1,413,630 bytes)

9. Upload that file to your 1and1 root directory
10. Create a php.ini file
    (I use a text editor like notepad or textpad)
    Add the following lines:

    zend_optimizer.optimization_level=15
    zend_extension=/homepages/xx/dxxxxxxxxx/htdocs/ZendOptimizer.so

    (replace the x’s with your location)

11. Upload php.ini to your 1and1 root directory
12. Upload php.ini to the root of the directory that you installed StoreStacker

1and1 gives you the choice of running PHP 4 or 5 on your sites and scripts.
The default (due to Apache) throughout your server will be PHP4.

To tell Apache to use PHP 5 instead of PHP 4 for the extension .php, you must add a few lines to your .htaccess file. The instructions will affect the directory the .htaccess is placed in and all sub-directories under it.

Add the following lines to your .htaccess file.

x-mapp-php5 .php
AddType x-mapp-php5 .php