Using the DD-WRT firewall - The Silicon Underground
dfarq.homeip.net › dd-wrt-firewallJul 29, 2016 · The first step is to enable the DD-WRT firewall, which you’ll find on the Security tab under the heading SPI Firewall. First, make sure the firewall is enabled on your Internet-facing DD-WRT router. Navigate to Security, Firewall, and check the box next to SPI Firewall. This poorly explained setting keeps Internet traffic off your local network.
Iptables command - DD-WRT Wiki
https://wiki.dd-wrt.com/wiki/index.php/IptablesIt is used to set up, maintain, and inspect the tables of IP packet filter rules in the Linux kernel. Iptables commands can be entered by command line interface, and/or saved as a Firewall script in the dd-wrt Administration panel. I tend to recommend testing and confirming your rules at the command line first.