Using Let's Encrypt for SMTPS

Can I use my certificate for SMTPS run with exim4 on Debian 11

My domain

I ran this command:

It produced this output:

My web server is (include version): Apache 2.4

The operating system my web server runs on is (include version): Debian 11

My hosting provider, if applicable, is: Hostinger

I can login to a root shell on my machine (yes or no, or I don't know): Yes

I'm using a control panel to manage my site (no, or provide the name and version of the control panel):

The version of my client is (e.g. output of certbot --version or certbot-auto --version if you're using Certbot):

The answer to your question might be answered by the FAQ:

Does Let’s Encrypt issue certificates for anything other than SSL/TLS for websites?

Let’s Encrypt certificates are standard Domain Validation certificates, so you can use them for any server that uses a domain name, like web servers, mail servers, FTP servers, and many more.

Email encryption and code signing require a different type of certificate that Let’s Encrypt does not issue.


Does the version of exim4 that's available under Debian 11 support SMTPS? If so, does it use standard x.509 certificates? Consult its documentation to see. And if the answer to both questions is "yes," then you can use a cert from Let's Encrypt for that purpose.


The answer to both questions is yes. Thanks for the correction of the previous answer

1 Like

It really isn't a correction, though perhaps the FAQ could be more clear. The first paragraph quoted above says that LE certs can be used for any server that uses a domain name including mail servers--that's the relevant part of the answer for your question. The "email encryption" mentioned in the second paragraph is talking about encrypting emails as the end user, specifically using S/MIME. That, like code signing, requires a different type of cert.


You are right, sorry jamesapp. I should have read the FAQ more carefully. Important for me is that I have my answer. Thanks to both of you.


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