On Tue, Oct 04, 2022 at 06:00:55PM +0200, Michael wrote: > I am trying to set up a postfix 3.5.13 server as a destination for > multiple null-clients, but am failing with verifying the client's > self-signed client certificate. Are self-signed certificates > prohibited from this kind of verification?
Sure, but not with smtpd_tls_req_ccert = yes which requires that the client-certficate pass verification up to a known trust-anchor, instead set: smtpd_tls_ask_ccert = yes and then refuse connections that are not permitted by a certificate check. > compatibility_level = 3.5 The major.minor syntax was introduced with Postfix 3.6, for Postfix 3.5 use "3". > relay_clientcerts = hash:/etc/postfix/relay_clientcerts_md5 > smtpd_client_restrictions = permit_inet_interfaces, permit_tls_clientcerts, > reject This will do, but I would advise SHA256 at this point: http://www.postfix.org/postconf.5.html#smtpd_tls_fingerprint_digest smtpd_tls_fingerprint_digest = sha256 and of course use sha256 keys in the table. -- Viktor.