Allow iptables rules for Zabbix Agents
iptables -I INPUT 1 -p tcp -s zabbix server IP-address --dport 10050 -j ACCEPT
iptables -I OUTPUT 1 -p tcp -s zabbix server IP-address --dport 10051 -j ACCEPT
iptables -I INPUT 1 -p tcp -s zabbix server IP-address --dport 10050 -j ACCEPT
iptables -I OUTPUT 1 -p tcp -s zabbix server IP-address --dport 10051 -j ACCEPT