ebtables : Utility that enables basic Ethernet frame filtering on a Linux bridge, MAC NAT and brouting ( http://ebtables.sourceforge.net/ )
iptables : Linux kernel (2.4+) firewall, NAT and packet mangling tools ( http://www.netfilter.org/projects/iptables/ )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a musl
For Paludis use this rsync : rsync://gentoo.zugaina.org/musl-portage
If you have a problem : ycarus(-at-)zugaina.org