Postfix: Untrusted TLS connection established

How to link the ca-certificates in your Postfix configuration.

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By. Jacob

Edited: 2023-08-09 00:26

Untrusted TLS connection established

By randomness I discovered I had misconfigured my TLS certificate settings on my postfix server. A command you can use to check for this is:

grep -ri "Untrusted TLS connection" /var/log/mail.log

1. To fix this issue you may need to load the CA-Certificates in Postfix configuration:

sudo postconf -e 'smtp_tls_CAfile = /etc/ssl/certs/ca-certificates.crt'
sudo postfix reload

Alternatively, open up the /etc/postfix/main.cf file and add it to the end of the file manually. E.g:

smtp_tls_CAfile = /etc/ssl/certs/ca-certificates.crt

2. After doing this you can try to grep for trusted TLS... in the mail.log:

grep -ri "Trusted TLS connection" /var/log/mail.log

It should output Trusted TLS connection established in the terminal, which means the ca-certs were linked successfully.

If this is not working, repeat the last step after installing the CA-Certificates:

sudo apt install ca-certificates