Well, it depends on your setup (local, virtual) ?
For local setup, install vacation from: http://pkgs.org/centos-6/puias-x86_64/vacation-1.2.7.0-7.puias6.x86_64.rpm.h... and then follow guide at http://www.ducea.com/2008/11/05/howto-setup-vacation-using-postfix-on-debian... debian specific entries like ("aptitude or apt-get")
-- Eero
It is virtual machine. Thank you for your link.