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Re: [suse-security] Curious response



Hi again


On Saturday 13 December 2003 19:42, Keith Roberts wrote:

> I have tried altering my from address in Pine 4.44, under
> SuSE 8.1 pro.
>
> When I try to send the mail to suse-security@xxxxxxxx with a
> dummy from address in the header from, Pine gives me the
> following error message:
>
> Mail not sent: <keith@xxxxxxxxxxxxxxxx>
>
> Sender address rejected:
>
> Domain not found.
>
> This may be pine checking the header from, not
> suse-security@xxxxxxxxx

Yes, I think so too. The reason for this is probably that pine uses 
the from address you specified also as envelope sender address. 
Therefore, it checks if the domain part of the address exists.


> So I change this header from address in Pine to:
>
> <keith@xxxxxxxxxxxxxxxxxx>
>
> With that address, it gets past pine, but hasn't made it to
> this list yet!  (It may bounce back soon!)

I have the same problem with KMail. KMail doesn't check the address 
I enter in the From-field and delivers it to the SMTP server I use. 
But the mail disappears in the nirvana of the internet :-)

I don't think that you will get a bounce-back. Ezmlm will try to 
reach you at keith@xxxxxxxxxxxxxxxxxx, but since that is a fake 
address, you will not see this mail again either.

The problem seems to be, that all (common) mail user agents create 
the envelope sender address using the from address. I googled a bit 
to find a solution to this. The only evidence I found is that it is 
possible to configure the sending mail server (e.g., running 
postfix) in a way that it rewrites the mail headers.


> Have you got an http:// address for the mailing-list FAQ
> please?

As far as I know, the list ``test-list@xxxxxxxx'' is not archived. 
It is only used for test purposes by whoever wants to test 
something. I subscribed today when I was puzzling around with KMail 
and got the FAQ by sending a message to test-list-help@xxxxxxxxx 
The FAQ contains only one more question than the one I already sent 
you earlier today, so I will just paste it in here:


FAQ - Frequently asked questions of the test-list@xxxxxxxx list.

(Well, OK.  A test list really doesn't have frequently asked
questions but people who have trouble subscribing to mailing
lists do)

Q1.  I subscribed using the web interface on your web site and
     receive list mail fine but everytime I try to post it
     bounces back with a nasty message about only letting
     subscribers post.  Your system is broken.

A1.  Most likely your problem is that your envelope from and
     header from do not match.  You need to contact me 
     (ml-admin@xxxxxxxx) and ask to have your subscription
     address changed.  Make sure you state what address you
     are currently subscribed as.  If you don't remember what
     address you subscribed as please forward (don't bounce it) 
     *all* of the headers from from one the messages you've
     received.

     You can also just subscribe the correct address by emailing
     listname-subscribe@xxxxxxxx and following the instructions.
     Of course, you will then be subscribed twice and receive
     all list traffic twice--just email the custom address
     located in the List-Unsubscribe header in a posting
     delivered to the incoreect address.

Q2.  Envelope from?  Header from?  All I want to do is post a
     message to one of your mailing lists!  Why is this so
     complicated?  I don't have trouble subscribing to other
     mailinglists.

A2.  The header from is probably what you think of as the "from";
     e.g. 
        From: foo@xxxxxxx
     It is contained in DATA portion of the mail (that's the part
     of the mail that you, as a user, write).  The envelope from
     is written by your mail transport agent, or MTA.  That's the
     thing that your mail client hands the message you just wrote
     off to to have it delivered.  An envelope is generally
     represented as this in the traditional mbox format:
        From foo@xxxxxxx Fri Mar  1 12:59:36 2002
     If you use maildirs or some other mailbox format you probably
     won't have that. Most MTAs copy the envelope from to the
     Return-Path header so you can also get it from that. 
     This is who your MTA, in the words of RFC 822bis, says "the
     author(s) of the message, that is, the mailbox(es) of the
     person(s) or system(s) responsible for the writing of the
     message.''
     The mailing list software we use (ezmlm+idx) takes the envelope
     from as the address to subscribe when you email
     LISTNAME-subscribe@xxxxxxxxx  Other mailing list software might
     use the header from.

     There are lots of good technical reasons why the envelope from 
     is used (which you can read all about at the author's site:
     http://cr.yp.to/immhf.html) but a big benefit for you is that
     since the envelope from isn't displayed in list postings and
     the header from is ignored you can set your header from to be
     whatever you want.  This means that you can use your main email
     address for the list and, if you munge the address, you won't
     need to worry about it being harvested by an an evil spammer.
     In other words, you are encouraged rot13, reverse, encrypt,
     or do whatever to your header from (*except* leave it
     unqualified) and it won't affect your subscription at all. 



--
Check the headers for your unsubscription address
For additional commands, e-mail: suse-security-help@xxxxxxxx
Security-related bug reports go to security@xxxxxxx, not here