On 8/18/2011 11:39 AM, Thomas Berger wrote:
Am Donnerstag, 18. August 2011, 15:23:28 schrieb Jeroen Geilman:
On 2011-08-18 14:59, Reindl Harald wrote:
587 is AUTHENTICATED submission
Says who ?
Port 587 is AUTHORIZED submission, NOT AUTHENTICATED.
A limitation to a local network ist also a kind of authorization.
Either way, we seem to be adding confusion to the original question.
I like to 'think about' ports as highway routes. If you are connected to
'bigprovider.com', they know you are a user because you are connected
(sent login information), so using 'mail.bigprovider.com' on port 25 is
open... the highway route is open inside of the town so to speak. But,
there is a roadblock on the edge of town (bigprovider.com) and they have
a detour set up to use highway 587 instead, so the only way out of town
is route 587. Anyone living in town (on that providers internet
connection) must take the detour to get outside to another town
(mail.someotherprovider.com).
I'm slowly seeing most providers closing port 25, some even one
area/region at a time (Verizon comes to mind). So far for my clients,
all have 587 available and working when 25 is blocked.
If you aren't the internet service provider and if you allow more than
only webmail access, you pretty much have to have 587 set up for use
both in firewall settings and mailserver conf. Other ports and settings
may also be needed for TLS connections which is becoming the default in
most email clients these days.
A side note... some public connections, like internet cafe's do not
allow sending any email through any port. Only webmail works in those
locations. I suppose this is a good idea to prevent a visiting spammer
from compromising your reputation.
If you allow email client access, such as Outlook, your customer is
exactly right that your system is not providing a top or full level of
service.
John Hinton
------------------------------------------------------------------------
Thomas Berger
- Certified Linux/Cisco Networking Engineer -
BOREUS Rechenzentrum GmbH
Zur Schwedenschanze 2
D - 18435 Stralsund
Germany
Phone:+49 (0) 38 31 - 36 76 415
Fax: +49 (0) 38 31 - 36 76 615
eMail: t...@boreus.de
Internet: http://www.boreus.de/
--------------------------------------------------------------------------
Geschäftsführer: André Jahns, Holger Lebrecht
Handelsregister: Amtsgericht Stralsund HRB 5750
Sitz der Gesellschaft: Stralsund
