1. Concatenate your private key and the certificate issued into a PEM file:


cat mail_linuxia_de.key mail_linuxia_de.crt > /etc/courier/imapd.pem

  1. Copy the bundle file with the intermediate certifcates into the configuration directory for Courier:


cp mail_linuxia_de.ca-bundle /etc/courier

  1. Add the location of these files to the IMAP SSL configuration file, e.g. /etc/courier/imapd-ssl:


TLS_CERTFILE=/etc/courier/imapd.pem

TLS_TRUSTCERTS=/etc/courier/mail_linuxia_de.ca-bundle