[Dovecot] Dovecot proxying with LDAP - an example?

[Graham Leggett]

Hi all,

I have been struggling trying to understand the syntax to configure dovecot as a proxy against an LDAP server.

As a single server dovecot works great. Now I want to add the "mailHost" attribute which, if present, should indicate the DNS name of the host that contains the person's mailbox. If the mailHost matches the local hostname, the mailbox should be served locally as it already does now. If the mailHost is not the local hostname, dovecot should proxy the request to the given server using SSL on port 993.

The docs at http://wiki2.dovecot.org/PasswordDatabase/ExtraFields/Proxy suggest that proxy_always is what I am looking for, but I cannot find any worked examples of how this might work. Has anyone attempted this before? What I have so far is this, but no proxying seems to take place:

pass_attrs = mail=user,userPassword=password,\
  mailMessageStore=userdb_mail,=proxy_always=y,mailHost=host,=ssl=yes

Can anyone confirm?

I am using dovecot v2.0.9 as provided out the box by RHEL6.

Regards,
Graham
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