In order to install Zend Guard Loader, we need to download the extension from the Zend Downloads Page. It will download a tarball file, that we will have to uncompress.

$ tar -xzf ZendGuardLoader-php-5.3-linux-glibc23-x86_64.tar.gz

Once we have uncompressed the file, we will proceed with the installation. The extension is already compiled, so we just need to copy the binary file into the extensions directory:

$ cp ZendGuardLoader-php-5.3-linux-glibc23-x86_64/php-5.3.x/ZendGuardLoader.so /usr/local/php53/lib/php/extensions/no-debug-zts-20090626/

Now, we need to enable the extension by creating an INI file inside /etc/php53/conf.d

# /etc/php53/conf.d/zend_guard.ini
zend_extension = /usr/local/php53/lib/php/extensions/no-debug-zts-20090626/ZendGuardLoader.so
zend_loader.enable = 1

And that’s it, our extension has been installed. Now, we neet to restart Apache to reload the php configuration. You can restart Apache from the Control Panel or by executing the following command:

# On Ubuntu and Debian
$ service apache2 restart

# On CentOS
$ service httpd restart

Once installed, you should see it loaded when running php -i or with phpinfo().