I went to sslforfree gave my csr info to them and I recieved 2 files from them: 1. ca_bundle 2. certificate.crt

I also have my original mydomain.key & the mydomain.csr I then put my .key and certificate.crt files in the exact same places you'll also find dovecot.pem, same permissions and owners, I also symlinked those files to /etc/dovecot/private , I then restarted postfix and dovecot, my mailserver works great, in testing it at https://ssl-tools.net/mailservers that The mailservers of mail.mydomain.net can be reached through an encrypted connection I'm getting this error saying "Unknown Authority" even though it shows the Authority: Certificate chain

    89 days remaining 2048 bit sha256WithRSAEncryption 
    Unknown Authority 
    Let's Encrypt Authority X3 

I'm running Ubuntu 18.04 postfix, dovecot, sasl, spamassassin and Webmin everything updated to latest daily. I've been trying to figure this one out for about 2 weeks 12 hours per day, I could really use some help !

1 Answer 1


I "FINALLY" figured it out, Ilyak - I've been learning for like 2 weeks now everything I can. In my case I have 3 files 1. hostname.key I produced 2. ca_bundle.crt 3. certificate.crt

with postfix and dovecot it is obviouse where the first 2 go, I finally found 1 postfix setting that had an entry where I could give it the path example:
"TLS certificate authority file" : /etc/pki/dovecot/private/ca_bundle.crt , I couldn't find one for dovecot, it completes the chain through postfix only, re-tested and VIOALA all green now.

So from what I gathered, is it seems like this may have changed over different versions, One link above like many others I've tried suggest making all 3 files into 1, now the postfix I have on Ubuntu 18.04 takes all three files without any modification, in fact every time I catted more than one together, it wouldn't work at all. So all I ever had to do was make my key, make a csr, use the csr info to get a cert and then download the 2 files from sslforfree and set the path to 2 files in dovecot and all 3 in postfix restart both and done. When I need to replace the certificate I will use the same names and just download them replacing the old ones and restart dovecot and postfix.

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