Re: Enabling STARTTLS in Exchange 2003 IMAP service?

From: Andrew Biggs (dreamcoder_at_yahoo.com)
Date: 01/11/05 

Date: Tue, 11 Jan 2005 11:08:04 -0700

Thanks for the response Ben. You are correct that STARTTLS is in fact
an SMTP verb, but it is also an IMAP verb (see section 6.2.1 of
RFC-3501). This section describes a means for "upgrading" an ordinary
cleartext IMAP connection to a TLS encrypted connection, very much like
  how it is done in SMTP. In order to use it, however, the server must
advertise support for the STARTTLS command as part of it's response to
the CAPABILITY command. It is in getting Exchange 2003 to advertise
support for this capability that I am having difficulty.

Andrew

Ben Winzenz [Exchange MVP] wrote:

> I think you may be misunderstanding what IMAP is used for. IMAP is a
> mailbox viewing protocol. It stands for Internet Message Access Protocol.
> The STARTTLS command is an SMTP verb, not an IMAP command. What you are
> looking at is simply the ability to connect to the IMAP server via an SSL
> port. The standard (non-SSL) IMAP port is 143. If you enable SSL, then the
> port is 993, not 143.
>
> Since the STARTTLS command is an SMTP verb, this would be enabled on your
> SMTP Virtual server. Enabling TLS here would allow outgoing SMTP messages
> to be encrypted, but would also require that the host you are sending to
> accept them. TLS is not an extremely common implementation in mail servers.
> Meaning, although Exchange supports TLS, both the sending server and
> receiving server must be configured to enable it. If you want to see if
> your server supports it, simply telnet on port 25 and issue an EHLO command.
>

Relevant Pages

  • Re: Enabling STARTTLS in Exchange 2003 IMAP service?
    ... You are correct that STARTTLS is in fact ... cleartext IMAP connection to a TLS encrypted connection, ... > The STARTTLS command is an SMTP verb, ...
    (microsoft.public.exchange2000.protocols)
  • Re: Enabling STARTTLS in Exchange 2003 IMAP service?
    ... You are correct that STARTTLS is in fact ... cleartext IMAP connection to a TLS encrypted connection, ... > The STARTTLS command is an SMTP verb, ...
    (microsoft.public.exchange.admin)
  • =?ISO-8859-1?Q?Re:_SMTP-Zertifkat_remote_pr=FCfen?=
    ... Obskur finde ich, dass STARTTLS bevorzugt wird, obwohl es den Client ... ein eigener Port keine sonderlich gute Idee ist. ... Was fuer ein Bloedsinn. ... IMAP mit "S wie Sicherheit" ist, andere Leute werden sich die Sache ...
    (de.comp.security.misc)
  • Re: SMTP-Zertifkat remote =?iso-8859-15?Q?pr=FCfen?=
    ... Obskur finde ich, dass STARTTLS bevorzugt wird, obwohl es den Client ... Bei IMAP ist STARTTLS problematisch, ... Was fuer ein Bloedsinn. ... warum ist STARTTLS dann bei SMTP kein ebenso grosser Nachteil? ...
    (de.comp.security.misc)
Loading