On Oct 24, 2015, at 11:02 PM, Randy Bush <randy@xxxxxxx> wrote: >> The requirement in v6 that didn't exist in v4 is that you have to have a >> PTR record for your MTA's IPv6 address before Google wants to let you >> send SMTP over IPv6. > > and spf > > randy If you don’t have spf your mail is going to get scored way down my my mailer too. SPF is an IETF standard, so you really can’t complain that Google are scary renegades for using it.