https://devopsnotebook.com/index.php?action=history&feed=atom&title=Basic_iptables_firewall_template 2026-04-23T17:29:20Z Revision history for this page on the wiki MediaWiki 1.33.1 https://devopsnotebook.com/index.php?title=Basic_iptables_firewall_template&diff=351&oldid=prev 2021-12-14T08:59:09Z

<p>Created page with &quot;&lt;pre&gt; # Flush INPUT/OUTPUT/FORWARD chains iptables -F INPUT iptables -F OUTPUT iptables -F FORWARD # Drop invalid packets iptables -A INPUT -m conntrack --ctstate INVALID -j...&quot;</p> <p><b>New page</b></p><div>&lt;pre&gt;<br /> # Flush INPUT/OUTPUT/FORWARD chains<br /> iptables -F INPUT<br /> iptables -F OUTPUT<br /> iptables -F FORWARD<br /> <br /> # Drop invalid packets<br /> iptables -A INPUT -m conntrack --ctstate INVALID -j DROP<br /> <br /> # Pass everything on loopback<br /> iptables -A INPUT -i lo -j ACCEPT<br /> iptables -A OUTPUT -o lo -j ACCEPT<br /> <br /> # Accept incoming packets for established connections<br /> iptables -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT<br /> <br /> # Accept incoming ICMP<br /> iptables -A INPUT -p icmp -j ACCEPT<br /> <br /> # Accept incoming SSH <br /> iptables -A INPUT -p tcp --dport 2020 -j ACCEPT<br /> <br /> # Allow HTTP and HTTPS<br /> iptables -A INPUT -p tcp -m multiport --dports 80,443 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT<br /> iptables -A OUTPUT -p tcp -m multiport --dports 80,443 -m conntrack --ctstate ESTABLISHED -j ACCEPT<br /> <br /> <br /> # Accept SQL Connections on specific interface<br /> iptables -A INPUT -i ens19 -p tcp --dport 3306 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT<br /> iptables -A OUTPUT -o ens19 -p tcp --sport 3306 -m conntrack --ctstate ESTABLISHED -j ACCEPT<br /> <br /> <br /> # Accept outgoing connections<br /> iptables -P OUTPUT ACCEPT<br /> <br /> # Drop everything else on INPUT/FORWARD<br /> iptables -P INPUT DROP<br /> iptables -P FORWARD DROP<br /> <br /> &lt;/pre&gt;</div>

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