Open a port in CentOS

After CentOS is installed, only port 22 is enabled by default. If you want to open other ports, you need to open the required ports.
For example, open the default http port 80.
Edit iptables

Vi/etc/sysconfig/iptables

vi /etc/sysconfig/iptables

Add

-ARH-Firewall-1-INPUT-mstate -- stateNEW-mtcp-ptcp -- dport3001-jACCEPT

-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 3001 -j ACCEPT

Restart the service

/Sbin/serviceiptablesrestart

/sbin/service iptables restart

Check whether the port is open

/Sbin/iptables-L-n

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#/Sbin/iptables-I INPUT-p tcp-dport 80-j ACCEPT
#/Sbin/iptables-I INPUT-p tcp-dport 22-j ACCEPT
Then save:
#/Etc/rc. d/init. d/iptables save
After the computer is restarted, ports 80 and 22 are enabled by default.
You may not restart the computer either here:
#/Etc/init. d/iptables restart
Close the firewall and close its services:
View Firewall Information:
#/Etc/init. d/iptables status
Disable the Firewall Service:
#/Etc/init. d/iptables stop
Permanently close? I don't know how to use the permanent method:
# Chkconfig-level 35 iptables off
Check whether there are already:
[Root @ vcentos ~] #/Etc/init. d/iptables status