Can't write the guide for you, but the raw material can be found here (and other places): http://www.ipdeny.com/ipblocks/data/aggregated/au-aggregated.zone http

Can't write the guide for you, but the raw material can be found here (and other places): http://www.ipdeny.com/ipblocks/data/aggregated/au-aggregated.zone http://www.ipdeny.com/ipblocks/data/aggregated/au-aggregated... That's a list of the (current) IPv4 Australian blocks. Each value (e.g. 1.0.4.0/22) can be used directly as a parameter for iptables on Linux, e.g. /sbin/iptables -A INPUT -s 1.0.4.0/22 -j DROP (to really block any communication - or use REJECT instead) A script to walk through the file works fine.