Shorewall (IPv4 support package for shorewall)

The Shoreline Firewall, more commonly known as "Shorewall", is a
Netfilter (iptables) based firewall that can be used on a dedicated
firewall system, a multi-function gateway/router/server or on a
standalone GNU/Linux system.

As of version 4.5, shorewall consists of 3 packages:
* shorewall-core, containing the common elements to both IPv4 and IPv6
  components
* shorewall, the IPv4 component
* shorewall6, the IPv6 component

The shorewall-core package is needed for both but now you can install
the IPv6 packages without needing the IPv4 one if you are on aIV6
network only.