> I'm seeing periodic entries like this in my maillog:
>
> Dec 12 13:12:47 xavier postfix-116/smtpd[1683671]: warning: TLS library
> problem: error:0A000438:SSL routines::tlsv1 alert internal
> error:ssl/record/rec_layer_s3.c:1584:SSL alert number 80:
[...]
> smtp_tls_cert_file=/etc/letsencrypt/fullchain.pem
> smtp_tls_key_file=/etc/letsencrypt/privkey.pem
usually there is no need for client certificates when sending emails.
> smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
> smtp_tls_exclude_ciphers = MD5, RC4, 3DES, IDEA, SEED, aNULL
> smtpd_tls_security_level = may
> smtpd_tls_exclude_ciphers = MD5, RC4, 3DES, IDEA, SEED, aNULL
> tls_preempt_cipherlist = yes
> smtpd_tls_mandatory_ciphers = high
> smtpd_tls_auth_only = yes
> smtpd_tls_cert_file = /etc/letsencrypt/fullchain.pem
> smtpd_tls_key_file = /etc/letsencrypt/privkey.pem
Are you sure cert/key_file path is correct?
Those filenames look like they are generated by certbot, wich places files
(softlinks) in
/etc/letsencrypt/live/<servername>/{fullchain.pem,privkey.pem,...},
not in /etc/letsenrypt/{fullchain.pem,...} on my server.
Did you check if the certificate is valid?
openssl x509 -text < /etc/letsencrypt/cert.pem
openssl x509 -text < /etc/letsencrypt/live/<servername>/cert.pem
// cert.pem contains your public certificate only whereas fullchain.pem
// additionally contains letsencrypt's intermediate certificate.
// For verification try cert.pem for smtpd_tls_cert_file use fullchain.pem
Best regards
Gerald
