Mailinglist Archive: opensuse (3337 mails)

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Re: [SLE] SMTP authentication
  • From: "Hylton Conacher (ZR1HPC)" <hylton@xxxxxxxxxxxx>
  • Date: Sat, 29 Apr 2006 13:19:41 +0200
  • Message-id: <44534BCD.9050404@xxxxxxxxxxxx>
Greg Wallace wrote:
On Thursday, April 27, 2006 @ 9:33 AM, Hylton Conacher wrote:

<snip>

OK, so , assuming a mail has to take the long path to get to the email destination and therefore goes from local SMTP to ISP SMTP to intermediary SMTP to destination SMTP and that the intermediary SMTP needs authentication. However because it cannot see my local server, due to it having dropped its dialup connection or whatever, it does other tests to obtain authentication.

If you send mail to a 3rd party SMTP while logged into your local ISP, your
local ISP SMTP server doesn't even get involved. Maybe I'm misreading your
above paragraph, but it sounds like you might be thinking it does get
involved.
Sorry Greg, a slight mis-read/misunderstanding on your/my side. As I understand an SMTP server must send its load to another SMTP server. To clarify let us assume there are only 3 SMTP servers in the world ie my local one, my ISP's one, the destination one.

Me-- |A|----------Broken link--------------|B|
\ /
\---------Link OK-------|C|--------/

Me=My Mozilla-mail on my local machine
A= My local SMTP server
B= Destination SMTP server
C=My ISP SMTP server acting as relay between A and B

Let us assume that A cannot see the destination B. It determines that the alternate path to B is via C.

The destination (B) does not need to authenticate the messages it receives however C does. So while my local SMTP server is connected and sending mail to C, C does authentication and sees that the FROM header in some of the emails is not the same as the email address as the person logged onto the ISP. C therefore drops those messages into the forever ether. The messages whose FROM header is the same as the person dialed in are relayed to the destination server (B).

Can the above happen to a local SMTP server (A) as it has been happening to Me when I sent email directly from my Mozilla Mail to C. If the FROM header in some of the emails is not the same as the email address as the person logged onto the ISP. C therefore drops those messages into the forever ether. The messages whose FROM header is the same as the person dialed in are relayed to the destination server (B).

<snip>

I hope the above better explains my concerns.


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