In setting up my new mail server, I am getting the following in the logs:

Oct 11 07:10:59 kumo dovecot[5704]: imap-login: Disconnected (no auth attempts in 0 secs): user=<>, rip=24.53.79.10, lip=172.26.12.90, TLS handshaking: SSL_accept() syscall failed: Success, session=<B9OokqCUD+UYNU8K>

I have tried various ssl_protocols entries, but for now have defaulted back to ssl_protocols = !SSLv3 (the "out of the box" setting).

The certificate (ssl_cert = </etc/ssl/certs/certificate_and_key.crt) is valid and the same one used by postfix.  However, I belive the error appeared only after removing the self signed certificate and installing the one I purchased.

Warning:  though I was a sysadmin a long long time, it has been a while!  I have not run a mail server in 15 years, but am moving my mail back "in-house" as I approach retirement!  I searched for a forum where I could post this issue, but only found this list.



# 2.2.33.2 (d6601f4ec): /etc/dovecot/dovecot.conf

# Pigeonhole version 0.4.21 (92477967)
# OS: Linux 4.15.0-1051-aws x86_64 Ubuntu 18.04.1 LTS
auth_mechanisms = plain login
mail_location = maildir:~/Maildir
mail_privileged_group = mail
managesieve_notify_capability = mailto
managesieve_sieve_capability = fileinto reject envelope encoded-character vacation subaddress comparator-i;ascii-numeric relational regex imap4flags copy include variables body enotify environment mailbox date index ihave duplicate mime foreverypart extracttext
namespace inbox {
  inbox = yes
  location =
  mailbox Drafts {
    special_use = \Drafts
  }
  mailbox Junk {
    special_use = \Junk
  }
  mailbox Sent {
    special_use = \Sent
  }
  mailbox "Sent Messages" {
    special_use = \Sent
  }
  mailbox Trash {
    special_use = \Trash
  }
  prefix =
}
passdb {
  driver = pam
}
plugin {
  sieve = ~/.dovecot.sieve
  sieve_dir = ~/sieve
}
protocols = " imap sieve pop3"
service auth {
  unix_listener /var/spool/postfix/private/dovecot-auth {
    group = postfix
    mode = 0660
    user = postfix
  }
}
ssl_cert = </etc/ssl/certs/certificate_and_key.crt
ssl_cipher_list = ALL:!ADH:!LOW:!EXP:!aNULL:+HIGH:+MEDIUM
ssl_client_ca_dir = /etc/ssl/certs
ssl_key =  # hidden, use -P to show it
userdb {
  driver = passwd
}
protocol lda {
  deliver_log_format = msgid=%m: %$
  mail_plugins = sieve
  postmaster_address = postmaster
  quota_full_tempfail = yes
  rejection_reason = Your message to <%t> was automatically rejected:%n%r
}
protocol imap {
  imap_client_workarounds = delay-newmail
  mail_max_userip_connections = 10
}
protocol pop3 {
  mail_max_userip_connections = 10
  pop3_client_workarounds = outlook-no-nuls oe-ns-eoh
}