What I want to do is block all traffic and only allow lan to wan traffic on certain ports. The ports would be 21 (ftp), 22 (ssh), 25 (smtp), 53 (dns), 80 (http), 110 (pop3), 443 (https), and icmp (ping and traceroute). I guess I would need a rule to block / drop traffic and rules to allow traffic on certain ports. Is this possible with iptables and if so what are the correct commands to do so. I'd try to figure it out myself, but iptables confuses me.