Ran into a small issue with a colleague’s email getting flagged as spam. SpamAssassin, didnt like the fact that his PC (which defaults to IPv6 if available) didnt have PTR record. As Windows 7 has IPv6 privacy extensions on by default there was no PTR record to match to an A record. Generally this was a no-no in ipv4 days, but in IPv6 days, its err… not practical. To quote http://tools.ietf.org/html/draft-howard-isp-ip6rdns-00
[to create a /48 worth of ptr records] If 1000 entries could be written per second, the zone would still not be complete after two quintillion years.
OK, so thats not gonna happen here….And asking all outside mail servers to “fix” this check is not going to happen there either 🙁 Dont really like many of the options listed in the RFC either… Dynamic DNS, hacking up DHCP6 (What happened to the benefits of SAC?)…. Hmmmm