This is without even getting into learning the new (old?) paradigm of "exposing" all addresses to the whole internet. I realize "NAT" is not equivalent to "firewall", but placing them at the same boundary made things simple to understand conceptually. I for one never had trouble opening/forwarding ports (and liked the control it provided over what goes in and out, especially in the days before it all just became HTTP) but I sympathize with the major headaches the NAT "workaround" caused.