Hi, according to [1] since 2.8 postfix uses ipv6 as default for smtp_address_preference. But as stated in the doc, it is unsafe as only IPv6 connectivity is broken, so the safe variant would be any.
Wouldn't it be an alternative that smtp_address_preference could be set to "ipv6, ipv4" or "ipv4, ipv6" instead of any? Kind regards Bjoern [1]http://www.postfix.org/postconf.5.html#smtp_address_preference
