crossroad

forward

make your router serve as a router

block

blocking of specific ports

dnat

port forwarding to machines on internal lan

masquerade

make the internet believe packets from the lan come from the firewall

The basic reason of existence of crossroad, compared to other scripts that do the same things, is the fact that it is easy to specify the configuration. This is because the configuration file allows grouping of iptables rules in a logical manner. You can specify a rule in the config file to forward four ports and two protocols coming in over two external interfaces in one rule. crossroad will resolve this into 4 * 2 * 2 = 16 iptables rules.

A sample rule might be

$DNAT{"DNAT WWW traffic"} = {
  "in-interface" => "ext",
  proto => "tcp",
  dport => "http https",
  "to-destination" => "192.168.1.2"
};

The latest source release of crossroad is 0.1.2 (2003-04-15).
Get other versions and packages from the crossroad download area.