I finally found how to search for useful gentoo iptables information and it's something those new to iptables won't think obvious. The trick is to search for gentoo netfilter tutorial OR howto on google.com. netfilter appears to be the larger project encompassing iptables and ipchains and ip6tables. The other tip on reading stuff about iptables on the web is to remember with firewalls you close everything down first then open up certain specific access paths. You will find misinformation on the web advocating setting up specific access paths first then denying everything else. It doesn't work that way according to peter.youssef at navy.mil, denying everything as the last rule in a firewall breaks all specific access paths you defined in earlier rules and leaves you with a closed system. Cybercrackers can and do write web pages too.
