Trying to send email to an account and getting this failure.

: Host or domain name not found. Name service error for type=AAAA: Host not found

Currently Microsoft doesn’t support IPv6 for, or Postfix by default if IPv6 is enabled will attempt a IPv6 DNS lookup, the AAAA record, this will fail as Microsoft doesn’t publish AAAA records for either domain. Current work around is to disable IPv6 in Postfix’s configuration:



inet_protocols = all


inet_protocols = ipv4

Then restart postfix:

service postfix restart

Changing postfix to qmail which will use the primary IP of the server ( to send messages for all accounts is a great way to change the sending IP to one that is not blacklisted.

Qmail default IP
default mail ip in /var/qmail/control/outgoingip