摘录自官方文档
Zabbix frontend on RHEL 6 is not supported because of PHP version. Since Zabbix 3.0 the requirements are to have PHP 5.4.0 or later while RHEL 6 latest version is 5.3.3 .
In most cases Zabbix server and frontend are installed on the same machine. When upgrading 2.2 to 3.0 Zabbix server will perform database upgrade and frontend will stop working. There is no way to roll back the database changes so users will be forced to upgrade PHP using 3rd party packages. This is why Zabbix server is also deprecated on RHEL 6.
If you still want to use Zabbix frontend on RHEL 6 and upgraded your PHP using 3rd party packages you would need to enable zabbix-deprecated repository first:

* open file /etc/yum.repos.d/zabbix.repo

* find section [zabbix-deprecated]

* set enabled=1

* save the file

You will have to do some more manual configuration. This is because we cannot identify the Apache version required for your PHP which makes it impossible for us to provide proper Apache configuration for Zabbix frontend. We have included 2 Apache configuration files to our zabbix-web package,one for Apache 2.2 and another for 2.4,which you would need to integrate with the Apache configuration yourself:

* httpd22-example.conf

* httpd24-example.conf