Man, you gotta have plenty of time ;-)
It's called VERP - Variable envelope return path
http://en.wikipedia.org/wiki/Variable_envelope_return_path
Every 1 of X mails is sent out with a variable header. That's a compromise between mail server load / traffic and undeliverable mail address detection.
No reason to worry. This is all on purpose ;-)
Stefan
* Carl-Daniel Hailfinger c-d.hailfinger.devel.2006@gmx.net [071124 13:17]:
Hi,
(yes, I read mail headers.) I have noticed that mails I receive via the list can have two differing Return-Paths, depending on some random circumstances. Both of the following header lines have been seen for mails sent 3 seconds after each other, differing in amost nothing except the Return-Path:
Return-Path: linuxbios-bounces+c-d.hailfinger.devel.2006=gmx.net@linuxbios.org Return-Path: linuxbios-bounces@linuxbios.org
The Return-Path variation is independent of the original sender, I have seen it for autogenerated commit mails as well as mails for every single person I checked.
Is anybody else seeing this?