Why the from and the sender are not the same thing?

[Jonathan Arcand]

Hi,

I received some messages like this:


> The following e-mail messages were found to have viruses in them:
>
>    Sender: <Webmaster at cegeptr.qc.ca >
> Recipient: <infoprog at cegeptr.qc.ca>
>   Subject: Scrolling
> MessageID: g7KE78FF002666
>    Report: /g7KE78FF002666/Yzdsr.scr        Found the W32/Klez.h at MM virus
!!!
> Windows Screensavers often hide viruses in email in Yzdsr.scr
>
> Full headers are:
>  Return-Path: <g>
>  Received: from Jcdyf (hurricane-ppp29.sorel.cognicase.net [64.254.11.35])
>   by courrier.cegeptr.qc.ca (8.12.5/8.12.5) with SMTP id g7KE78FF002666
>   for <infoprog at cegeptr.qc.ca>; Tue, 20 Aug 2002 10:07:09 -0400
>  Date: Tue, 20 Aug 2002 10:07:08 -0400
>  Message-Id: <200208201407.g7KE78FF002666 at courrier.cegeptr.qc.ca>
>  From: webmaster <webmaster at johnabbott.qc.ca>
>  To: infoprog at cegeptr.qc.ca
>  Subject: Scrolling
>  MIME-Version: 1.0
>  Content-Type: multipart/alternative;
>   boundary=BBowx3aO8i4OBHwS930B5Us0800A2M03
>
> --
> MailScanner
> Email Virus Scanner

I don't understand why the sender is webmaster at my.domain and in the header
is webmaster at johnabbott.qc.ca

The user's auto-response goes to webmaster at cegeptr.qc.ca

I'm using mailsanner 3.20-7 with no spam detection and Mcafee

Somenone knows what is my problem?
Thanks!

Jonathan