Post-OpenBSD 4.7 improvements

OpenBSD 4.8 and 4.9 had few user visible changes to PF (but the logging system was cleaned up), bug fixes, IPv6 related fixes, including fragment handling

The Next Big Thing: New traffic shaping subsystem (aka the beginning of the end for ALTQ), at first prio keyword for per rule priority (5.0)

The proxies (ftp-proxy, tftp-proxy) changed to divert(4), use divert-to in rules (5.0)

In OpenBSD 5.1 we saw NAT64 implemented with af-to, plus misc IPv6 sanity injections