Centos 7 save iptables settings

Problem: iptables resets to default settings after server reboot.

I'm trying to set rule like this:

iptables -I INPUT -p tcp --dport 3000 -j ACCEPT

after that I do:

service iptables save

and it writes back something like this

iptables: Saving firewall rules to /etc/sysconfig/iptables:[ OK ]

and after this I just ran (this was done once):

chkconfig iptables on (I have read that this has to be done in order to restore settings after reboot)

After that I reboot and run this command:

systemctl list-unit-files | grep iptables

and I see that iptables.service is enabled, however, the rule (to open port 3000) does not work anymore.

How do I persist these settings?

CentOS 7 is using FirewallD now! Use the --permanent flag to save settings.

Example:

firewall-cmd --zone=public --add-port=3000/tcp --permanent

Then reload rules:

firewall-cmd --reload

Disable firewalld by the following command:

systemctl disable firewalld

Then install iptables-service by following command:

yum install iptables-services

Then enable iptables as services:

systemctl enable iptables

Now you can save your iptable rules by following command:

service iptables save

On CentOS 7 Minimal you may need to install the iptables-services package (thanks to @RichieACC for the suggestion):

sudo yum install -y iptables-services

And then enable the service using systemd:

sudo systemctl enable iptables.service

And run the initscript to save your firewall rules:

sudo /usr/libexec/iptables/iptables.init save

iptables-save > /etc/sysconfig/iptables

will save the current configuration without the need to install any other libraries or services.