Step 1 – Add Required Repository

CentOS/RHEL 7:
rpm -Uvh http://repo.zabbix.com/zabbix/3.4/rhel/7/x86_64/zabbix-release-3.4-2.el7.noarch.rpm

CentOS/RHEL 6:
rpm -Uvh http://repo.zabbix.com/zabbix/3.4/rhel/6/x86_64/zabbix-release-3.4-1.el6.noarch.rpm

Step 2 – Install Zabbix Agent

yum install zabbix-agent

Step 3 – Edit Zabbix Agent Configuration

# vim /etc/zabbix/zabbix_agentd.conf

#Server=[zabbix server ip]
#Hostname=[ Hostname of client system ]

Server=192.168.1.11
Hostname=Server1

Step 4 – Restarting Zabbix Agent

# systemctl restart zabbix-agent

Step 5 – open the firewall port

firewall-cmd --permanent --zone=public --add-port=10050/tcp
firewall-cmd --reload
firewall-cmd --list-all