On 05/01/2021 11:02, Pierre-Philipp Braun wrote:
I thought CNAME in an MX record was considered naughty. Bind zone validation used to warn about it but did accept it. I know it was frowned on the last time I read the various e-mail RFCs but that could easily have changed since then ;)Besides, to solve the forward-confirmed-reverse-dns issue, I would also KISS over there and use a single and IPREV FQDN for both v4 and v6 IPs, be it delivered as a host from one of the two domains you are targeting, or simply another domain of yours that they would share an MX record from. As a side-note, it's possible to have a CNAME as an MX record, but it's just simpler and safer to point to the MX who's hosting those domain's email, directly.I get 2 public ips from the cloud provider - one is ipv4 and one ipv6.
Mike