[stunnel-users] Connecting stunnels

Ludolf Holzheid lholzheid at bihl-wiedemann.de
Wed Mar 30 15:49:35 CEST 2016


On Wed, 2016-03-30 12:45:25 +0000, Juhasz Gabor wrote:
> Hi Ludolf,
> 
> Thanks for you reply.
> 
> Yes, I mean how you wrote.
> 
> Could you write the name of this feature or doc to understand how it works.

Hi Gabor,

I don't have a link to post, but you don't need any special feature of
stunnel.


The idea is to have two instances of stunnel, one of them on the
client's host and the other on the server's host.

The client connects to the local stunnel instance (which is to be run
in client mode, 'client = yes').  This stunnel instance establishes an
encrypted connection to the instance on the server's host, which in
turn sets up a clear-text connection to the server (which is to be run
in server mode, 'client = no').

For instance, to encrypt a telnet connection:

  client's host            server's host
 +---------------+       +----------------+
 |               |       |                |
 | telnet client |       |  telnet server |
 | 127.0.0.1:x   |       |    127.0.0.23  |
 |  :            |       |     ^          |
 |  :            |       |     :          |
 |  V            |       |     :          |
 | 127.0.0.1:23  |       |    127.0.0.1:z |
 | stunnel       |       |        stunnel |
 | 1.2.3.4:y ===============> 5.6.7.8:992 |
 |               |       |                |
 +---------------+       +----------------+

The vertical connections (with colons) are clear-text, the horizontal
connection (with equal signs) is encrypted.


Ludolf

-- 

Ludolf Holzheid
 
Bihl+Wiedemann GmbH
Floßwörthstraße 41
68199 Mannheim, Germany
 
Tel: +49 621 33996-0
Fax: +49 621 3392239
 
mailto:lholzheid at bihl-wiedemann.de
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