greylist

Since a few months now, my email server use greylist to prevent spam. I have found it work well with one exception: mails sent from gmail.

gmail uses several smtp servers for outgoing mail, and while the use the same FQDN, the IP is different, which means every new try to deliver the same message will be greylisted.

The solution is simple: add *.google.com on a line of its own in /etc/greylistd/whitelist-hosts