[stunnel-users] Incoming port ignored

Ludolf Holzheid lholzheid at bihl-wiedemann.de
Wed Mar 30 10:50:07 CEST 2016

On Wed, 2016-03-30 09:58:59 +0200, Ivan De Masi wrote:
> [..]
> I examined the log and what makes  me wonder is, that the when fetching the
> e-mails, the configured ports (110/143/25) seem to be ignored:
> "Service [df-pop3s] accepted connection from" or "Service
> [df-pop3s] accepted (FD=472) from"


This is as expected.

Your mail client opens a socket which gets (presumably implicitly)
bound to an arbitrary TCP port (1878 and 1882 in the examples above).
It then connects to port 110, the one stunnel bound the listening
socket to.

Each IP connection has two ends and thus two pairs of IP address and
port number.  In your case, both, client and server use as
IP address, which may be the source of the confusion.




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
Sitz der Gesellschaft: Mannheim
Geschäftsführer: Jochen Bihl, Bernhard Wiedemann
Amtsgericht Mannheim, HRB 5796

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