port 587

Hello,
some of my users are having problems reaching my server
through port 25 
because their isp blocks that port. I tell them to use ssl
and port 465 
and things work. I was wondering why kolab wasn't listening
on port 587 
(mail message submission) with tls enabled. Is this just an
oversight or 
is there a deeper reason?
Cheers
Tobias Oed

-- 
*Tobias Oed* - Octant Informatique <http://www.octant-fr.com
>
contact | tobias.oedoctant-fr.com <mailto:tobias.oedoctant-fr.com> -
04 76 50 82 38
image

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On Thu, Mar 20, 2008 at 1:45 PM, Tobias Oed
<tobias.oedoctant-fr.com> wrote:
> Hello,
>  some of my users are having problems reaching my
server through port 25
>  because their isp blocks that port. I tell them to use
ssl and port 465
>  and things work. I was wondering why kolab wasn't
listening on port 587

Nobody know about port 587, nobody use it !

Port 587 must be able to do the same job as port 25, their
is no difference
between sending or receiving and email when you send an
email to
yourself on your own server!
Then why have 2 ports ?
When someone came with port 587 long time ago, SPAM was
"unknown" and
openrelay was "the rules".
Today the rules must be strict and the same for
"sending" and receiving.
Also 465 is smtpS with a for Secure or SSL and must force
the use of
authentication.

Regards.



Because of spam

>  (mail message submission) with tls enabled. Is this
just an oversight or
>  is there a deeper reason?
>  Cheers
>  Tobias Oed
>
>  --
>  *Tobias Oed* - Octant Informatique <http://www.octant-fr.com
>
>  contact | tobias.oedoctant-fr.com
<mailto:tobias.oedoctant-fr.com> -
>  04 76 50 82 38
>  image
>
>  _______________________________________________
>  Kolab-users mailing list
>  Kolab-userskolab.org
>  https:
//kolab.org/mailman/listinfo/kolab-users
>



-- 
Alain Spineux
aspineux gmail com
May the sources be with you

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On 2008/03/20 14:03, Alain Spineux <aspineuxgmail.com> wrote:
> On Thu, Mar 20, 2008 at 1:45 PM, Tobias Oed
<tobias.oedoctant-fr.com> wrote:
> > Hello,
> >  some of my users are having problems reaching my
server through port 25
> >  because their isp blocks that port. I tell them
to use ssl and port 465
> >  and things work. I was wondering why kolab wasn't
listening on port 587
> 
> Nobody know about port 587, nobody use it !
> 

Some people do. My included. I sometimes use an open hotspot
which does
not allow port 25 connections to the Internet.

> Port 587 must be able to do the same job as port 25,
their is no difference
> between sending or receiving and email when you send an
email to
> yourself on your own server!

The crucial point is ".. to yourself on your own
server".
How can an ISP tell the difference? 

He can't. He only knows:

* connections to port 25 can be used to transmit spam to all
mailservers
* connections to port 587 require that the client
authenticates at that
  server using AUTH, thus these connections cannot be used
to dump
  spam at random servers.

> Then why have 2 ports ?
> When someone came with port 587 long time ago, SPAM was
"unknown" and
> openrelay was "the rules".

Quite the contrary. Mail submission on port 587 combined
with out-going
port 25 filtering is one of the simplest ways to stop
zombified customers
from spamming.

Port 25 filtering for residential customers is mandated by
the local
telecom regulator in Finland. See
http:/
/www.ficora.fi/en/index/palvelut/palvelutaiheittain/tietotur
va/svt/kayttaja/kaytannonkysymyksia.html

/ol
-- 
-=-  Otmar Lendl  --  olbofh.priv.at  -=-

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