Steps: 1. Update your system #yum update 2. Install prerequisite pakages for Zimbra #yum install sudo sysstat libidn gmp libtool-ltdl compat-glib vixie-cron nc perl libstdc++.i686 3. Modify /etc/host file #vi /etc/hosts like this: 127.0.0.1 localhost localhost.local domain serverip hostname save it 4. Disable startup service a. chkconfig postfix off b. service postfix off c. chkconfig ..