[Dovecot] Trying nonplaintext mech with LDAP password-hash

[dovecotlist at encambio.com]

Hello List,

The only passdb block in /pfx/etc/dovecot/dovecot.conf is:

  passdb ldap {
    args = /pfx/etc/dovecot/dovecot-ldap.conf
  }

In /pfx/etc/dovecot/dovecot-ldap.conf:

  auth_bind = no
  dn = cn=mymgr,dc=host,dc=tld
  dnpass = ********
  default_pass_scheme = LDAP-MD5

In /pfx/etc/openldap/slapd.conf:

  password-hash {MD5}

If I try:

  $ /pfx/bin/ldapsearch <...> \
      | grep '^userPassword' \
      | sed -e 's;.*:: \(.*\)$;\1;' \
      | mimencode -u

...I get the correct password (MD5 hashed.)

According to wiki.dovecot.org/AuthDatabase/LDAP/PasswordLookups this
should work, and indeed when starting dovecot it does not complain
about:

  'CRAM-MD5 mechanism can't be supported with given passdbs'

Instead it starts right up, but when a thunderbird client
connects and tries authenticating with CRAM-MD5 it fails.

In the wiki page 'PasswordLookups' it mentions:

  Supports non-plaintext authentication mechanisms (if
  returning plaintext/properly hashed passwords).

I've already verified that this works correctly with plaintext
(CLEARTEXT in slapd.conf), but I really want to store the passwords
in LDAP using some hash. Why doesn't LDAP-MD5 work as advertised?

What did the author mean by 'properly hashed passwords'? Thanks.

-- 
Eduard