dovecot as proxy and verification of the backends certificate

11 Oct 2015


      Hello,
I'm using a dovecot as proxy, connecting to one or more backends.
The backends use X.509 certificates.
The proxy's passdb returns
extra fields:
user=foo
proxy
host=backend1.&lt;domain>
ssl=yes
nopassword=y
Thus the proxy connects to the backend but can't verify the backends
certificate.
The following comment suggests using ssl_client_ca_file for that.
# Directory and/or file for trusted SSL CA certificates. These are used only
# when Dovecot needs to act as an SSL client (e.g. imapc backend). The
# directory is usually /etc/ssl/certs in Debian-based systems and the file is
# /etc/pki/tls/cert.pem in RedHat-based systems.
#ssl_client_ca_dir = 
#ssl_client_ca_file =
ssl_client_ca_file = /tmp/certs/ca-local.pem
But that does not work! Instead I've to use  ssl_ca
# PEM encoded trusted certificate authority. Set this only if you intend to use
# ssl_verify_client_cert=yes. The file should contain the CA certificate(s)
# followed by the matching CRL(s). (e.g. ssl_ca = &lt;/etc/ssl/certs/ca.pem)
# ssl_ca = 
ssl_ca = &lt;/tmp/certs/ca-local.pem
Bug or feature? Mainly I'm asking because the comments do not indicate
that I should have used ssl_ca for this type of operation (dovecot as a
SSL client)
Best regards from Dresden/Germany
Viele Grüße aus Dresden
Heiko Schlittermann
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