Hi Viktor

Seeing that the domain ends in .dk - can you send me some uncensored details of 
the domain - then I can see if I have a contact, so I can reach out to the 
right entity?

Kind Regards,
Sidsel Jensen

Architect of Deliverability and Abuse @ Open-Xchange

> On 10/24/2023 7:33 PM CEST Viktor Dukhovni <[email protected]> wrote:
> 
>  
> The DANE survey (https://stat.dnssec-tools.org) turns up a few domains
> a day that botch their cert rollovers or fail to offer STARTTLS despite
> publishing DANE TLSA records.
> 
> I try to send notices to the relevant contacts, but sometimes they
> shoot themselves in the foot:
> 
>     - Private WHOIS
>     - No contact data at the website
>     - Published contacts don't work (no such user, ...).
>     - Reject earnest notices of technical problems as spam
> 
> Yesterday, for the first time, I ran into someone whose MTA stopped
> offering STARTTLS, despite the TLSA records still being in place, but
> attempts to deliver a notice are rejected:
> 
>     posttls-finger: < 220-mail.<censored>.dk ESMTP Postcow
>     ... brief pause...
>     posttls-finger: < 220 mail.<censored>.dk ESMTP Postcow
>     posttls-finger: > EHLO <...>
>     posttls-finger: < 250-mail.<censored>.dk
>     posttls-finger: < 250-PIPELINING
>     posttls-finger: < 250-SIZE 104857600
>     posttls-finger: < 250-ETRN
>     posttls-finger: < 250-AUTH PLAIN LOGIN CRAM-MD5
>     posttls-finger: < 250-AUTH=PLAIN LOGIN CRAM-MD5
>     posttls-finger: < 250-ENHANCEDSTATUSCODES
>     posttls-finger: < 250-8BITMIME
>     posttls-finger: < 250-DSN
>     posttls-finger: < 250 CHUNKING
>     posttls-finger: > QUIT
>     posttls-finger: < 221 2.0.0 Bye
> 
> The notice bounced with:
> 
>     550 5.7.1 Session encryption is required (in reply to RCPT TO command)
> 
> As commendable as it may be to encourage use of TLS, it is not a good
> practice to outright refuse cleartext mail.
> 
> -- 
>     Viktor.

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