#DANE
Heise.de: Let's Encrypt verkürzt Laufzeit von Zertifikaten auf 45 Tage
Dear OpenSource developers: Please support DANE in your libraries and applications. That will help us to be independent of the CAs.

Some days ago I renamed one of my MX records to be more streamlined. This prompted me to look at all the DNS records. Only though this, I noticed that only one of my MX records has a suitable #DANE #TLSA record. So it might be a good idea for you to check if they are all how they should be. For me, this means the following:
mynacol.xyz MX -> mx1.mynacol.xyz, mx2.mynacol.xyz
mx1.mynacol.xyz A/AAAA
_25._tcp.mx1.mynacol.xyz TLSA ... <- This was missing
mx2.mynacol.xyz A/AAAA
_25._tcp.mx2.mynacol.xyz TLSA ...
Mit DANETOOL danetool --check sieht mein Mail-Server gut aus. Aber FairEmail mag sich dennoch nicht via DANE mit dem Server verbinden. Hmpf.
Immerhin, DNSSEC akzeptiert er.
@kmj I looked into this about a year ago. The situation boils down to this: If the receiving domain has set up #DANE #TLSA and the sender tries to send with DANE and is somewhat RFC compliant, it does use TLS #SNI during STARTTLS, which allows to forward an encrypted connection to the actual destination. If DANE is not used, almost all mail clients don’t use TLS SNI by default. This leaves a reverse proxy with needing to decrypt the connection with a self-signed/bogus certificate or an unencrypted connection to get to know where to forward the mail to. There also seems to be no way to get the intended recipient from the client and then instruct the client to “restart” the sending of the same mail while offering TLS and forwarding it to the correct destination.
I learned at the same time that https://v4-frontend.netiter.com/ by @kasperd does the above thing on port 25. If DANE resp. TLS SNI is used, an encrypted connection is forwarded as-is. All other traffic is decrypted and forwarded to the intended recipient based on the plaintext RCPT TO.
Hm, FairEmail in Verbindung mit DNSSEC und DANE ist nicht immer problemlos.
Mein Mail-Server unterstützt beides (das einzurichten, hat mich auch viel Zeit gekostet), aber FairEmail kann dennoch keine Mails versenden, wenn auch nur eines von beiden aktiviert ist.
Beim Versand via Mailbox.org (die ebenfalls beides unterstützen) derzeit das gleiche Spiel.
(DNSSEC und DANE sorgen grob gesagt dafür, dass der Mail-Server, der Mails zum Versand entgegennehmen will, auch wirklich der ist, der er zu sein vorgibt und kein Schwindler, der nur so tut als ob.)

Chceli väčší byt a onA rozmýšľala nad živnosťou. Konsolidácia vlády Roberta Fica takto zmarila plány mladej rodiny z Prievidze. Vďaka vyšším daniam a odvodom prídu ročne o stovky eur. Nie sú pritom jediní - Rada pre rozpočtovú zodpovednosť po hĺbkovej analýze rozpočtu priniesla údaje o koľko eur prídu ročne rodiny na Slovensku.
Miss Amelia murders a purple bat toy at super speed. #Dane #Chiweenie #SillyPuppy #Play
A Chiweenie Great Dane mix playing with a purple bat toy and a Human.