spf-discuss
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Fwd: Re: Maybe simple question

2003-12-13 06:01:54
Hello.

I never received this sent mail back from the list so I'm resending it.

If we look at the top few lines of your mail, we see:-

Return-Path: <owner-spf-discuss(_at_)v2(_dot_)listbox(_dot_)com>
Delivered-To: marrandy(_at_)chaossolutions(_dot_)org
Received: (qmail 5216 invoked from network); 12 Dec 2003 21:25:07 -0000
Received: from unknown (HELO apex.listbox.com) (207.8.214.5)
  by hooters.chaossolutions.net with SMTP; 12 Dec 2003 21:25:07 -0000


During the SMTP session.  client = MTA sending,  Server = MTA receiving  which 
in my case :

220 hooters.chaossolutions.net ESMTP

 If the server does not accept the connection, the client quits. 

The client then sends a HELO request, and waits for the response: 

     HELO apex.listbox.com
     250 hooters.chaossolutions.net

 If the server does not accept the request, the client quits. 

The client then sends a MAIL request showing the envelope sender address, and 
waits for the response: 

     MAIL FROM:<owner-spf-discuss(_at_)v2(_dot_)listbox(_dot_)com>
     250 ok

 If the server does not accept the request, the client quits. 

The client then sends one RCPT request for each envelope recipient address, 
waiting for a response after each address: 

     RCPT TO:<marrandy(_at_)chaossolutions(_dot_)org>
     250 ok

 It keeps track of which addresses are accepted. If none of the addresses are 
accepted, the client quits. 

The client then sends a DATA request, and waits for the response: 

     DATA
     354 go ahead


etc.  etc..

Is that clearer now.

spf is checking the :-

MAIL FROM:<owner-spf-discuss(_at_)v2(_dot_)listbox(_dot_)com> 
by stripping the left parts away leaving  listbox.com, looking it up in DNS 
(with the rule you are using, a, mx, ptr or whatever, and comparing it 
against the IP 207.8.214.5

If it matches, mail is being sent from a server in that domain.

Please provide corrections if necessary.

Regards...Martin

-- 
If the facts don't fit the theory, change the facts.
                -- Albert Einstein

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--- Begin Message ---
On Friday 12 December 2003 04:29 pm, Ned Harvey wrote:
Ok, so I understood it correctly from the start then.  Under SPF, the 
receiver's mailserver has to know the IP address that the message came from.  
But it doesn't.  It only knows the last relay that hands the message over.

Email is almost never a direct operation, Wechsler.  Look at your own 
messages.  The ones you send to this list go through 5 relays before 
arriving.

Even though I'm new to this list, I think I know why your confused.


Two points above.


The terminology is ambiguous and needs to be clarified.

http://www.infinitepenguins.net/SPF/index.php

is part of the problem.

They say (third entry)

Mail Sender (from: email addy)    (eg wechsler(_at_)infinitepenguins(_dot_)net) 

Which makes you think they are talking about the From:  in your mailer (MUA).

I suggest they change this to :-

MAIL FROM: (return path - MTA)   -  May or may NOT be the same as the FROM: in 
your MUA

which should help to clarify things.

Second point.  You must remember that each connection is a direct SMTP link.  
They are separate.  Each MTA add's some additional information, date/time, 
server receiving the mail and IP of the remote mail etc.
If that's it's final destination,. it is done.  If not it starts a new SMTP 
connection to another server.
This can depend on whether :-

They have multiple mail servers that pass it along (large systems).
A mailing list.
A mail forwarder.

The point to remember, is, that the MTA (mail server) that is processing the 
message, will change the return path to it's name, when it connects to the 
next MTA, it will say :-

MAIL FROM:  <with it's return path name>  NOT your original MUA (email 
address)  name.

It's late and I'm tired.  If it's still unclear, I will try again once i get 
some weekend choirs completed.

Regards...Martin
-- 
Hard work never killed anybody, but why take a chance?
                -- Charlie McCarthy

--- End Message ---