Receiving duplicate email from the list

[James Wilkinson]

Guido Leisker wrote:
> I got duplicated mails too. But that was only last week. Two or three 
> mails i got about 100 times!

OK. For what it's worth, I'm not.

The way to troubleshoot duplicate e-mails is to compare the headers from
two "duplicates" and see where you start getting different mail IDs.

For example, from the headers of your e-mail:

> Received: from hormel.redhat.com (hormel.redhat.com [209.132.177.30])
>         by mx.gmail.com with ESMTP id i10si4885401wxd.2006.01.14.01.37.54;
>         Sat, 14 Jan 2006 01:37:58 -0800 (PST)
> Received: from listman.util.phx.redhat.com (listman.util.phx.redhat.com [10.8.4.110])
>         by hormel.redhat.com (Postfix) with ESMTP
>         id E46F2731C5; Sat, 14 Jan 2006 04:37:43 -0500 (EST)
> Received: from int-mx1.corp.redhat.com (int-mx1.corp.redhat.com
>         [172.16.52.254])
>         by listman.util.phx.redhat.com (8.13.1/8.13.1) with ESMTP id
>         k0E9bcSR030932 for <fedora-list at listman.util.phx.redhat.com>;
>         Sat, 14 Jan 2006 04:37:38 -0500

Received lines can take slightly different formats, but these are all
the same: "Received: from <computer1> by <computer2> with ESMTP id
<id>... " The ID is the reference number of that e-mail through the
receiving computer. If you see the same ID for the same computer in both
duplicates, then that computer only processed the mail once. It got
"split" into two mails afterwards.

If you see different IDs for the same computer, then the two e-mails
passed through the computer separately.

If you see a different mail path (they went through different
computers), you really need to ask yourself "why?"

Incidentally, most duplicate e-mail around here has been due to a number
of dodgy POP3 servers [1]. The POP3 spec says that clients should
download e-mails and optionally delete them, but the server should not
actually delete any e-mails until the connection is closed properly.
This means that if the connection drops without being properly closed,
then next time you connect to the POP3 server, you'll get all your old
e-mail again...

Hope this helps,

James.

[1] A previous ISP and Gmail, FWIW...
-- 
E-mail address: james | "Drums must never stop. Very bad if drums stop."
@westexe.demon.co.uk  | "Why? What will happen if the drums ever stop?"
                      | "Bass solo."