Hi, > I've a generic question to all more experienced than me postfix users here: > Is it nowadays (reasonable) possible to run postfix with IPv6 only? E.g > "mail.example.com" and "smtp.example.com" with only ipv6 AAAA records in the > DNS, no A / ipv4 anymore?
I would not yet advise to run a mail system ipv6 only. > As I have a small VPS with only one IPV4 included in price, I've set the PTR > to "example.com" and not to "mail.example.com", which is the fqdn for my > outgoing postfix sent mail. > Of course I know that this is a "should not", but as there's a lot of stuff > running e.g. on Apache on this machine, a nextcloud instance, a TYPO3 > instance, roundcubemail, jitsi meet, ..., all on separate subdomains like > "cloud.example.com", "webmail.example.com", "meet.example.com" etc., I simply > don't like to have an "unclean" PTR, pointing not the main/base domain. > "Only" because of antispam. The forward/reverse dns has to match but some providers also verify the helo name (postfix outgoing fqdn). Why not run postfix with "example.com"? Other companies do not care if they deliver to example.com or mail.example.com. > As said I have only one IPv4 for my VPS, but a /64 IPv6 subnet. > So more than enough IPv6 addreses to give each of my few domains amd not that > many subdomains a unique IPv6, with a corresponding PTR. You can configure postfix to try ipv6 delivery first (which is the default for postfix 2.8+) http://www.postfix.org/postconf.5.html#smtp_address_preference > I'm only not sure if there might be "IPv4-only" email providers out there, > whose emails might not be routed to my "IPv6-only" postfix. That is possible. Best regards Gerald
