how to open port in centos code example

Example 1: centos 7 port open

firewall-cmd --zone=public --add-port=55555/tcp --permanent
firewall-cmd --reload

Example 2: open port 22 centos 7

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

#check if port 22 open
iptables-save | grep 22

#Remove  port 22
firewall-cmd --zone=public --remove-port=22/tcp --permanent
firewall-cmd --reload

##By iptables= add port 22
service iptables status
service iptables start
chkconfig --list iptables
chkconfig iptables on
iptables -L
#add port
iptables -A INPUT -i eth0 -p tcp --dport 22 -j ACCEPT
#delete port
iptables -D INPUT -i eth0 -p tcp --dport 22 -j ACCEPT

#check if port 22 open
iptables-save | grep 22