Sam Varshavchik писал 04.04.2013 2:47:
> Alexei Batyr writes:
> 
>> Sam Varshavchik wrote on 02.04.2013 3:17:
>>> Alexei Yu. Batyr' writes:
>>> 
>>>> Sam Varshavchik wrote on 31.03.2013 8:02:
>>>>> ...
>>>>> * Changed error handling when sending mail to mail servers that
>>>>> advertise that they can support encrypted SMTP, but fail to open 
>>>>> an
>>>>> encrypted connection once Courier takes up their offer. Removed 
>>>>> the
>>>>> /SECURITY=NONE option from esmtproutes. When sending mail to a
>>>>> server
>>>>> that advertises STARTTLS, but either subsequently rejects the
>>>>> STARTTLS
>>>>> request with an error message, or by dropping the connection, the
>>>>> mail
>>>>> is requeued, and the server's name is logged. Subsequent 
>>>>> connection
>>>>> attempts to the same server, to resend this message or send any
>>>>> other
>>>>> message, will ignore the server's STARTTLS capability. This is
>>>>> logged
>>>>> in a rotating log file, that's erased after 2-4 hours, at which 
>>>>> time
>>>>> the next connection attempt will once again attempt to use 
>>>>> STARTTLS,
>>>>> and see what happens.
>>>>> 
>>>>> * /SECURITY=REQUIRED replaces /SECURITY=NONE. If set, in
>>>>> esmtproutes,
>>>>> mail will not be sent to this mail server, without STARTTLS. Note,
>>>>> though, that this doesn't mean much, unless 
>>>>> ESMTP_TLS_VERIFY_DOMAIN
>>>>> is
>>>>> set to 1 in courierd (together with the additional variables that
>>>>> are
>>>>> documented there), which will require remote mail servers to use
>>>>> valid
>>>>> certificates signed by a trusted CA root.
>>>>> 
>>>> So, from this version on, I cannot maintain my STARTTLS-free SMTP
>>>> infrastructure (only explicit SSL on dedicated port). Would it be
>>>> possible to add some configure script parameter, e.g.
>>>> --smtp-starttls-disable, which will act as ":  /SECURITY=NONE" in
>>>> esmtproutes and remove STARTTLS advertizing from ESMTP greeting
>>>> (250-XSECURITY=NONE instead of 250-XSECURITY=NONE,STARTTLS)? Or at
>>>> least
>>>> leave /SECURITY=NONE as it was?
>>> 
>>> Not exactly sure what you're looking for, but to disable TLS
>>> completely, you just need to remove the couriertls
>>> binary. This will prevent Courier from sending mail using STARTTLS,
>>> without having to diddle with esmtproutes,
>>> and will prevent Courier's esmtpd server from advertising STARTTLS.
>>> This is true now.
>> 
>> Removing couriertls will also disable STARTTLS for IMAP and POP, 
>> won't
>> it? I'd like to do it only for SMTP service.
> 
> Try removing the COURIERTLS setting only from the courierd
> configuration  file. That should disable TLS for outgoing mail.
> 
> For incoming mail, remove the COURIERTLS setting from the esmtpd and
> esmtpd- ssl configuration files.
> 
> And the best part of this – you can change your mind at any time,
> without  recompiling.
> 
> But, I don't really see the point to this. The latest approach should
> be far  more tolerant of problems with bad servers choking on TLS; and
> there's no  downside to using encryption, these days. Modern hardware
> is fast enough,  the limiting factor is usually bandwidth.
> 
Probably you're right - it's time to rethink configuration built many 
years ago, IIRC exactly to avoid headache with misconfigured Exchange 
servers  and at the same time reduce load to the ancient hardware.


------------------------------------------------------------------------------
Minimize network downtime and maximize team effectiveness.
Reduce network management and security costs.Learn how to hire 
the most talented Cisco Certified professionals. Visit the 
Employer Resources Portal
http://www.cisco.com/web/learning/employer_resources/index.html
_______________________________________________
courier-users mailing list
[email protected]
Unsubscribe: https://lists.sourceforge.net/lists/listinfo/courier-users

Reply via email to