outlook hangs using TLS

Aki Tuomi aki.tuomi at dovecot.fi
Mon Jun 11 09:15:31 EEST 2018

On 09.06.2018 12:13, Jerry wrote:
> On Fri, 08 Jun 2018 21:00:29 +0200, ivanb.dsol stated:
>> -------- Original message --------
>> From: Jerry <jerry at seibercom.net>
>> Date: 6/8/18 20:59 (GMT+01:00)
>> To: Dovecot Mailing List <dovecot at dovecot.org>
>> Subject: Re: outlook hangs using TLS
>> On Fri, 8 Jun 2018 18:19:14 +0100, Vladimir Tiukhtin stated:
>>> On 08/06/18 18:17, Jerry wrote:
>>>> On Fri, 8 Jun 2018 17:54:28 +0100, Vladimir Tiukhtin stated:
>>>>> I am using dovecot 2.2.10 on CentOS 7
>>>>> Any Outlook versions (2007, 2010, 2013...) hang if I tried to use TLS,
>>>>> it works if I switch in client TLS to SSL. Thunderbird works perfect
>>>>> both scenarios  
>>>> {snip}
>>>> Seriously, those versions of Outlook are both old and no longer supported.
>>>> In any case, you have already answered your question; ie, use SSL.
>>> I have tested just now on outlook 2016 - same issue. TLS makes it hanged
>> I am using Outlook 2016 on a Windows 10 Pro amd64 system. Dovecot is running
>> on a FreeBSD 11.1 machine. Dovecot version: 2.3.1 (8e2f634). It is working
>> fine. What port numbers and authentication types are you employing?
>> Sent from my Samsung Galaxy smartphone.
>> A vide se postovi i kategorije... to sam propustio... obrisacu... pa
>> javljam....
> I don't speak that language. According to Google Translate, that means, "And
> you can see the posts and categories... I missed it... deleted... so I'm
> reporting...." I don't understand what you are referring to.

There are few reasons why this could be:

1. Your server has very little entropy, you can check this from
/proc/sys/kernel/random/entropy_avail, if it says a two-digit number,
you probably are going to need some entropy helper, if it's a big
number, you're fine.

2. Some clients don't like STARTTLS, try using SSL port instead.

3. You have some problem(s) in your client machine, verify with some
other machine.


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