TLS/SSL for SMTP-Server

Help
1

Hi 2 All.

Is it possible to get an TLS/SSL-Certification from Let's Encrypt for SMTP-Mail-Server?

2

Yes ... you'll need to validate the domain somehow (dns or http), but it works fine.

I use a LE certificate on my postfix mail server and it works great.

I did setup a dummy web site to validate the domain, but that's the only hoop I had to jump through.

3

Yes, you can even use most ACME clients in "standalone" mode and they will spin up a temporary web server to satisfy the HTTP authentication request [themselves].
[if you don't have a web server on that system and don't want to install one]

4
  1. I have certifications for my domains (SSL). Can I use them also for postfix or do I need to make separate?
  2. I have another SMTP-Server (OWN). All Domains are in my official DNS-Profiles. If 1 with own or same certification, can I use them also in this Server? It is a windows Server!!!!!!!

I use Postfix for sending adv-mails (faster) and the windowsserver for personal-mails.

5

If the hostnames in the certificate are also applicable for your mailserver, then you can use the same certificate.

6

Postfix for Windows?

Do they share the same FQDN?