To install zabbix agent in Oracle or Redhat 6 Linux

# yum remove zabbix-release
# yum install http://repo.zabbix.com/zabbix/2.2/rhel/6/x86_64/zabbix-release-2.2-1.el6.noarch.rpm
# yum clean all

CentOS/RHEL 6:
# rpm -Uvh http://repo.zabbix.com/zabbix/3.0/rhel/6/x86_64/zabbix-release-3.0-1.el6.noarch.rpm

# yum install zabbix-agent