Linux Administration Cookbook

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If you make changes with firewall-cmd or ufw, you can generally save the running config to the persistent config at the same time.

With iptables, we want to use iptables-save to modify our saved configuration, and ensure that it starts at boot:

$ sudo iptables-save# Generated by iptables-save v1.4.21 on Sun Aug 19 15:04:14 2018*filter:INPUT DROP [0:0]:FORWARD ACCEPT [0:0]:OUTPUT ACCEPT [3:236]-A INPUT -i eth1 -p tcp -m tcp --dport 22 -j DROP-A INPUT -s 10.0.2.0/24 -p tcp -m tcp --dport 22 -j ACCEPT-A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPTCOMMIT# Completed on Sun Aug 19 15:04:14 2018

This is all fine and dandy, except it's printed the configuration to standard out instead of saving it somewhere. Let's fix ...