I was actually looking for a test site that could do that, like we have dnssec-failed.org - saves me setting up the target servers themselves DANE requires a p

I was actually looking for a test site that could do that, like we have dnssec-failed.org - saves me setting up the target servers themselves DANE requires a provider to validate DNSSEC. I know not all of them do that. DANE takes it even a step further, so I'm going to assume even fewer providers implement that Microsoft specifically announced it last februari for Exchange Online (not really a SMTP SaaS like eg. send grid) so it's special enough that it's worthy of an announcement - https://techcommunity.microsoft.com/t5/exchange-team-blog/releasing-outbound-smtp-dane-with-dnssec/ba-p/3100920 https://techcommunity.microsoft.com/t5/exchange-team-blog/re... I emailed postmark if they supported STARTTLS/DANE, they replied they supported opportunistic STARTTLS. Not an outright "No" but might be a failure to understand the questions So plenty of reasons to not assume DANE is implemented unless a provider can actually confirm it is.