Clientcert.pem

clientcert.pem

Note, this file needs to contain the private key in addition to the SSL certificate. The CA chain might be required as well.

man qmail-remote excerpt:

SSL certificate that is used to authenticate with the remote server during a TLS session.

Usually a link to servercert.pem, e.g.:

ln -s servercert.pem clientcert.pem