[Dovecot] problem with disable_plaintext_auth

[Olivier Nicole]

Hi,

> > I am using dovecot with postfix for authentication.
> >
> > Everything (TLS/SSL, authentication) is working fine, except that when
> > I set:
> >
> >     disable_plaintext_auth = yes
> >
> > I still can authenticate with plain text on a no TLS/SSL session:
> >
> >     20 mail2.cs.ait.ac.th ESMTP Postfix (2.6.2)
> >     EHLO [192.41.170.57]
> >     250-mail2.cs.ait.ac.th
> >     250-PIPELINING
> >     250-SIZE 10240000
> >     250-VRFY
> >     250-ETRN
> >     250-STARTTLS
> >     250-AUTH PLAIN LOGIN
> >     250-AUTH=PLAIN LOGIN
> >     250-ENHANCEDSTATUSCODES
> >     250-8BITMIME
> >     250 DSN
> >     AUTH PLAIN XXXX
> >     235 2.7.0 Authentication successful
> 
> disable_plaintext_auth affects logging in to dovecot IMAP/POP3 server.  
> This is  a SMTP session with Postfix, you'll have to configure Postfix  
> not to allow plain text authentication before STARTTLS.

But postfix hands the authentication task to dovecot (dovecot-auth
daemon).

And I am sure it does, because if I remove PLAIN from the
authentication mechanism of dovecot, then the SMTP sessions with
postfix will not offer AUTH PLAIN anymore.

So I am confused here.

Best regards,

Olivier