Whose fault? vacation messages bounce to postmaster.

[mark london]

I am running cyrus/squirrelmail/sendmail.  I have a vacation plugin 
for squirrelmail and set up vacation autoresponding.  However, if 
vacation responds to a spam message that has a bogus email address, 
the bounced message that says that the vacation message can't be 
delivered to that bogus email address, goes to postmaster at our 
site, rather than the person who has vacation enabled.  I don't know 
if this is a feature or a bug, and how to  change it's behavior.  I 
notice that  thevacation autoresponse messages have a line at the top 
of message say that cyrus set sender to <>.  Is this possible the 
reason for this behavior?  Or is it a sendmail feature?  Here's the 
header of a vacation response message.  Thanks! -   Mark

X-Authentication-Warning: alcserv1.psfc.mit.edu: cyrus set sender to 
<> using -f
Message-ID: <[EMAIL PROTECTED]>
Date: Tue, 12 Aug 2003 09:21:16 -0400
X-Sieve: CMU Sieve 2.2
From: <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Subject: Re: test
In-Reply-To: <[EMAIL PROTECTED]>
Auto-Submitted: auto-replied (vacation)
X-Virus-Scanned: Message: ok
X-Spam-Level: 0 () IN_REP_TO,NO_REAL_NAME,X_AUTH_WARNING
X-Scanned-By: MIMEDefang 2.31 (www . roaringpenguin . com / mimedefang)