Config iptables to accept SSH port
Wiki » Config iptables to accept SSH port

Open Port 22(SSH) on CentOS/RHEL 7

firewall-cmd --zone=public --add-port=22/tcp --permanent
firewall-cmd --reload

Open Port 22(SSH) on CentOS/RHEL 6

iptables -I INPUT -p tcp -m tcp --dport 22 -j ACCEPT
service iptables save