[Dovecot] Enabling security on POP3 and IMAP

[Richard Hobbs]

Hello,

>> Is it possible to offer encrypted and non-encrypted services
>> simultaneously, so people have a choice of whether they want
>> security or not? I know that's a bit weird, but for testing
>> it would be useful.
>
> No problem. Basically you just need to specify the certificate
> (ssl_cert_file) and the key (ssl_key_file) in the config, and
> add 'imaps' and 'pop3s' to 'protocols'.

Thanks for the advice... however, it has only partially worked.

When i "check what the server supports" in Kmail when setting up a new
account in my email client, for POP3, it says it supports None, SSL and
TLS and defaults to TLS, and auth methods are Clear text and Plain.

Is there a way to get rid of the "None" method for encryption? I do not
have "pop3" in the protocols line - only "pop3s".

As for IMAP, the problem is worse... all i get for IMAP is "No
encryption with clear text passwords". SSL/TLS just doesn't seem to be
an option for IMAP despite "imaps" being in the protocols line and
"imap" *not* being there.

For both these tests, rightly or wrongly, i used the standard ports (110
for POP3, 143 for IMAP). I know SSL typically operates on higher ports
numbers, at least for IMAP, but I dont' know how this all works when you
turn off non-encrypted protocols.

Any advice gratefully received!

Thanks again,
Richard.


Patrick Nagel wrote:
> Hi Richard,
> 
> On 2009-09-03 16:38, Richard Hobbs wrote:
>> Currently, on our new test server, I am offering IMAP on 143 and POP3 on
>> 110.
> 
>> We would like to enable security on both of these protocols to attempt
>> to eliminate the risk from an internal
>> password-grabbing/content-grabbing attack.
> 
>> I presume this would mean enabling SSL, and a more securure
>> authentication, right? Or are plain text passwords just sent over the
>> SSL, and therefore perfectly secure?
> 
> Yes, plain text passwords are fine with SSL/TLS, since the connection gets
> secured before the password is sent.
> 
>> Also, what are the steps to enable security for these protocols on an
>> already-configured server?
> 
>> Is it possible to offer encrypted and non-encrypted services
>> simultaneously, so people have a choice of whether they want security or
>> not? I know that's a bit weird, but for testing it would be useful.
> 
> No problem. Basically you just need to specify the certificate (ssl_cert_file)
> and the key (ssl_key_file) in the config, and add 'imaps' and 'pop3s' to
> 'protocols'.
> 
>> Finally, is there a way to monitor which users are connecting over the
>> secure ports and which users are connecting over the non-secure ports?
> 
> You can see it in the log.
> 
> Patrick.
> 

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-- 
Richard Hobbs (IT Specialist)
Toshiba Research Europe Ltd. - Cambridge Research Laboratory
Email: richard.hobbs at crl.toshiba.co.uk
Web: http://www.toshiba-europe.com/research/
Tel: +44 1223 436999        Mobile: +44 7811 803377
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