“Version 2.6.12 of the Linux kernel is likely to include packet
filtering that will work with IPv6, the latest version of the
Internet Protocol.“Netfilter/iptables, the firewall engine that is part of the
Linux kernel, already allows stateless packet filtering for
versions 4 and 6 of the Internet protocol, but only allows stateful
packet filtering for IPv4. Stateful packet filtering is the more
secure method, since it analyses whole streams of packets, rather
than only checking the headers of individual packets–as is done in
stateless packet filtering…”