Hello Let's Encrypt community. I would like to know what type of software I should select on Certbot for a certificate that will be used for Mail (Postfix) running on Ubuntu.
Thank you,
Radostin
1 Like
Hi @raduoos, and welcome to the LE community forum 
That sounds like a general question for Postfix [forum]:
What type of certificate(s) can be used for Postfix version x.y.z?
Once you know the type(s), then we can help you ensure that certbot requests a type that works.
4 Likes
Hi @rg305 .
It's a digital certificate for TLS.
I am following the tutorial right here:
https://ubuntu.com/server/docs/install-and-configure-postfix#configure-tls
There are two main types of certs:
- RSA
- ECDSA
And then each have multiple size/strength choices.
Again: We don't know [for sure] which exact cert type(s) [and strengths] will work with your version of Postfix.
[this is NOT a Postfix forum]
4 Likes
There is a link on that page:
"See our guide on security certificates for details about generating digital certificates and setting up your own Certificate Authority (CA)."
That page only mentions one type of cert and only one size/strength:
Generating RSA private key, 2048 bit long modulus
Again/again: We can't be certain which other types/sizes may work with your version of Postfix.
But it seems like that type and size may work.
If you want to make certbot use that type/size, you will have to add this to the request:
--key-type rsa
[2048 size is the default for rsa, so you don't have to specify that part]
4 Likes
This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.